American V8 Engines

 

I’ve commented on the Pontiac 400 cubic inch V8, and the Chevrolet 305 V8.  Now I want to ease back and give you bigger picture.

Pull the cord on a gas-powered lawn mower, and you’ve got a single cylinder gas engine spinning a blade around to cut your lawn.  Look under the hood of a Citroen Deux Chevaux (DCV) and you’ll see a flat two cylinder engine.  Most economy cars have 4 cylinder engines, mostly inline, with Saab, VW and Porsche making flat 4s, and V4s exclusively in motorcycles.  Their upscale brethren can usually be found with six cylinder engines:  straight six (favored by BMW), V6s (most of the others), and flat sixes (Subaru and Porsche).  But the most epic of these is the V8.  Eight cylinders, two banks of four, generally 90 degrees apart.  The V8 replaced the straight (inline) 8, which lasted until the mid 1950s.

Despite the advent of modern electric motors, gasoline V8s are still around and will be for some time.  Even if electric cars completely replace ICE (internal combustion engines) on showroom floors, that does nothing about the millions of existing gas powered vehicles which won’t be magically transformed into electric cars overnight – if ever.  That being the case, they are still relevant, and thus V8s are still relevant as well.

Straight Eights.  While the V configuration (two banks of 4 cylinders at a 90 degree angle) is most common – and I haven’t seen a flat (horizontally opposed) 8 (Porsche used one in racing cars, but no production cars) – inline 8 cylinder engines were popular in the 1930s, 40s, and into the 50s before being phased out in favor of V8s.  Most American companies made straight eights, though Cadillac stuck with V8s, V12s and even V16s.  Buick’s straight eight was distinctive for using a more modern overhead valve format, while the rest of the straight eights used flathead (L head) engines. 

Flathead vs. overhead valve vs. overhead cam.   Flathead engines have the valves (intake and exhaust) in the block itself, leaving the cylinder head little more than a cover through which the spark plugs poke into the combustion chamber.  OHV and OHC engines have the valves in the cylinder heads.  OHV engines locate the camshaft, which opens and closes the valves, in the block, linked to the valves by lifters, pushrods, and rocker arms.  OHC engines put the camshaft(s) in the cylinder head itself, directly opening and closing the valves.  Although the OHC system is marginally superior, Chevrolet still uses the OHV format for its current LS engines. 

Ford Flathead (1932).  While Chevrolet had an ill-fated V8 in 1916, the first popular V8 was the Ford Flathead, debuting in 1932.  Instead of being a luxury car engine, this was mass-produced, so most Americans could drive a car with this V8.  Not only were the cars themselves popular, but the V8 started the trend of hot-rodding, birthing the performance aftermarket.  The main two displacements were 221 (3.6L) and 239 (3.9L), maxing out at 85 HP.  Although Cadillac (1948) and Oldsmobile (1949) came out with their overhead valve (OHV) (modern style) V8s earlier, it was the Small Block Chevy V8 (1955) which toppled the Ford Flathead from the throne.  Ford phased out the flathead in 1953, replacing it with its Y block (OHV) series in 1954.

Small Block Chevy 1955.  Introduced in 1955 in 265 cubic inches, later growing to 283 (1958), 327 (1962), 350 (1967), and 400 (1970), with the 305 (5.0L) coming into the picture in 1976 as a fuel-economy variant.  The 400 was never very popular, leaving the 350 (5.7L) as the optimal size for performance.  The SBC went into Novas, Camaros (in which the 350 debuted), Chevelles, Corvettes, Bel Airs, station wagons, vans, and pickup trucks – plus marine versions as well.  By 1998 the LS engines took over and are now the favored hot rod engines.  But while the SBC is no longer under the hood of anything you can go into a GM dealer and buy today, it’s still available as a crate engine from GM (as is the LS).

Innovations of the SBC:  very light – even lighter than the stovebolt (Chevrolet) straight six; well breathing cylinder heads with stud-mounted rocker arms (though it was Pontiac which invented this innovation); and a one piece intake manifold which also covered the lifter valley (contrast with Pontiac’s two piece manifold).   Mass produced with excellent power for its weight, the small block Chevy knocked the Ford flathead off its throne.   

The Big Three.   That would be General Motors, Ford, and Chrysler.   GM consists of Chevrolet, Pontiac, Oldsmobile, Buick, and Cadillac.  Ford includes Mercury, Edsel, and Lincoln.  Chrysler also includes Dodge and Plymouth (also known as"MOPAR").

Other, defunct car companies also made their own V8s; of these, American Motors (AMC) lasted the longest.  Popular displacements included 304, 343, 360, 390, and the largest, the 401.  Like many V8s of a given series, they were the same size externally; like Pontiac, AMC did not have “big blocks” or “small blocks”.  Oddball AMC models like the Gremlin and Pacer could be purchased with the 304 – and hotrodded with the 401, which would otherwise be in the Javelin (muscle car) or full size models.  Studebaker, Packard, and International Harvester also made their own V8s.

Hot Rodding.  An engine’s “displacement” is the cubic volume of its cylinders (leaving aside rotary engines, only made by Mazda, for the purpose of this discussion).  A cylinder has a height (stroke) and diameter (bore).  An engine makes power by bringing in air, mixing that with a specific ratio – 14.7:1 (stoichiometric) – of fuel, and igniting that mixture with a spark plug.  The larger the cylinder, the more air can be thus processed, and thus more power.  However, the bore and stroke are internal dimensions; the external dimensions generally remain the same.

Although Pontiac, unlike other GM divisions, did not have “small” and “big” blocks, it stratified its V8s into three parallel series.  The smaller engines, the 326 and 350, served as entry level.  The larger engines, the 389 and 400, were mid-level, and the larger engines, the 421, 428, and 455, were reserved for the full size cars – the Bonneville and Catalina.  However, all these engines are the same size externally.  One Saturday morning back in 1963, the Pontiac techs and engineers, led by John DeLorean, realized that the 389 V8 would drop into the entry-level sized LeMans in place of the 326 it was being sold with.  The 389-equipped LeMans was much faster and more fun to drive.  “Pity we can’t sell it with that engine,” they thought.  “Well, we can – as an option” – the GTO.  An instant success! 

GM vs. the others.  With Ford/Mercury and Chrysler, the corporate family shared engines across divisions.  Cadillac and Lincoln make their own engines, which have more in common with each other than with their division brothers.  GM, until 1982, had each division making its own, which caused some confusion.  Chevrolet, Pontiac, Oldsmobile and Buick all had 350 cubic inch V8s, all four being completely different.  All four had a 400 cubic V8, again all completely different.  Chevrolet’s largest big block was a 454, while Buick, Olds and Pontiac (“BOP”) all had a 455 – and all were different.

I have to laugh at this.  In the early 70s, GM started switching around V8s in its different divisions, without telling the customers, assuming they didn’t know or care – and many of them didn’t.  Until…one Oldsmobile customer (Joseph Siwek) brought his brand new 1977 Olds Delta 88 into the local Olds dealer for service.  The tech gave him back his Olds V8 parts, telling him the Chevrolet (not Oldsmobile) 350 V8 in his new car didn’t need them.  “Chevrolet V8?  But I bought an Oldsmobile!”  Tech shrugs, “I guess they’re putting Chevrolet V8s in Oldsmobiles now.”  This irate customer sued GM for false advertising and won.  They didn’t stop the policy, but the court ordered that they add a fine print disclaimer to the sales material warning customers that their GM vehicle might be equipped with an engine made by a different division of GM.  Automotive History: The 1977 Oldsmobile Chevrolet Engine Scandal – There’s No Rocket In My 88’s Pocket | Curbside Classic

The most pertinent example of this was when Pontiac stopped making V8s in 1981, and all 1982- (third and fourth) generation Firebirds wound up with a Chevrolet V8 under the hood.  This was even more tragic because until the 350 became available in 1987, the best Chevrolet V8 you could get in a Firebird was a 305, most of which struggled to reach 200 HP.  In addition to putting out considerably more horsepower than the 305, the 350 also puts out far more torque and responds much better to performance modifications, which is why it remains the most popular displacement of the classic small block Chevy V8. 

GM has a pecking order of its divisions.  The basic idea is that a GM customer would start out with a Chevrolet, and progressively upgrade to the other divisions as he/she got better jobs.  Trade your Chevrolet in for a Pontiac, trade your Pontiac in for an Oldsmobile, trade your Oldsmobile in for a Buick, and finally upgrade to a Cadillac.  Failing the last, most hearses (station wagons used to transport coffins) are made by Cadillac, meaning your last ride is likely to be in a Cadillac, even if you’re not alive to enjoy it.

Chevrolet.  I’ve already described the revolutionary small block.  In addition, there are two big block series.  The first was the W block variety, from 1958-64, in 348, 409, and 427 cubic inch displacements.  The 409 features in the Beach Boys’ song of the same name: “my four speed dual quad positraction 409”.  The valve covers look like inverted W’s, but the heads didn’t flow nearly well enough.  So they started from scratch with the big block (1965-76 in passenger cars), in 396/402, 427, and 454 displacements.  The big block remains in existence as a crate engine, a monster 632 cubic inch, 1000 HP behemoth, which will presumably drop in where a 396, 427 or 454 used to be. 

LS Engines.  With the notable exception of the ZL1 427, all Chevrolet V8s have iron blocks.  Corvettes received aluminum cylinder heads on its TPI engines, but the block itself remained iron.  In between the Tuned Port Injected 350 (L98) in Firebirds, Camaros and Corvettes was the LT1 V8, with aluminum cylinder heads, reverse flow cooling, and Optispark ignition, bringing power from 240 (L98) to 275 (LT1).  But GM started from scratch with an aluminum block for the LS engines, the current standard V8s.  4.8, 5.3 and 6.0L displacements are in trucks, 5.7L and 6.0L in Camaros and Corvettes, all the way up to 7.0L for its most powerful versions. 

Pontiac.  Its three series of V8s are noted above.  Add to this the 265/301 from 1980-81, a last-ditch effort, including turbocharging the 301 in Trans Ams and Formulas.  Pontiac brought its V8 out in 1955, the same year as Chevrolet.  As noted, Pontiac is closest to Chevrolet in the pecking order.  Oddly, when it came time to make the F body (Camaro and Firebird), Oldsmobile wanted in, but GM thought a third variant would thin the market out too much.  So they thew Olds the bone of allowing them to jazz up the Cutlass with the Hurst/Olds model in 1968, silver and black with the 455 V8.  Imagine an alternate universe where you have Oldsmobile F-bodies in 1967-69, 1970-81, 1982-92, and 1993-2002.  Mind.  Blown. 

As noted, Pontiac doesn’t have big or small blocks, and its V8s range from 326 to 455.  In addition to the small block, Chevy has the big block, generally in 396, 427, and 454 displacements.  Pontiac dropped 455s in Firebird Formulas and Trans Ams in the 1970s, from 1971-76, while Chevrolet never did the same with Camaros – and it phased out the 396 after 1972.  Dealers like Yenko (in Pennsylvania) or Baldwin-Motion (on Long Island) may have dropped 427s and 454s into Chevys themselves. 

Pontiac cylinder heads.  The standard heads have semi-circular exhaust ports, so-called “D” port.  The Ram Air II, IV, 455HO and SD455 heads have round ports.  The round port heads flow much better than the D ports, which is why those engines are the top Pontiac V8s.  When Edelbrock decided to make aluminum versions of Pontiac cylinder heads, they used the Ram Air IV heads as a starting point, although their aluminum heads actually have D ports – but the “D” is on its side.

My closest experience with Pontiac V8s came in 1998, when I purchased a 400 out of a Trans Am which had gone bad.  I put it on a stand in my parents’ garage and gradually broke it down to the block itself.  The machine shop confirmed that the block and crank were history, so they went into the trash.  The heads were “6X”, a later D-port variant (no Firebirds after 1974 have round port heads).  I took out all 16 valves and cleaned them, later having some of the parts bead blasted and painted.  I still have some of the parts (oil filler tube guide). 

Oh, and Pontiac is named after a famous Native American chief from the Detroit area.  Its earlier logo was an Indian head, and later switched to a down-pointing red arrowhead. 

Oldsmobile.  Oldsmobile was second, after Cadillac, to produce an OHV V8 (1949).  Small blocks include the 330, 350, and 403.  The 403 replaced the Pontiac 400 in 1979 Trans Am automatic transmission applications (“6.6 Litre”) for 185 HP, vs. the 4 speed manual Pontiac 400 (“T/A 6.6”) with 220 HP. Big blocks include the 400, 425, and 455.  Someone put an Olds 455 from a 1972 F-85 in my 76 Firebird.  Someday I might even get it running.  Olds V8s have rear mounted distributors and an oil filler tower in the front of the engine, as opposed to simply a cap on the valve covers most V8s use.

Oldsmobile’s logo features an uprising rocket, with “Rocket” frequently invoked in the name.  [Clutch: “My Rocket 88, fastest in the land, crucial, crucial, VELOCITY!”].    

Buick.  Small blocks range from their aluminum 215, all the way up to 350.  Big blocks include 400, 430, and 455.  Somewhat confusingly, the big block series replaced the first V8 series (1953-64) (the Nailhead, due to small valves) which ranged from 264 to 425 cubic inches, including a 401 cubic inch variant.  Buick V8s have front mounted distributors.    

Cadillac.  The first GM division to produce an OHV V8, in 1948.  This series lasted all the way the 1970s, ranging from 331 cubic inches all the way to 500 cubic inches, the largest displacement V8 engine ever available in a US car.  And since the Cadillac V8 isn’t much larger than any other, some hot rodders will drop a Cadillac 500 into another car. 

Northstar and Blackwing.  While the non-Chevrolet V8s – except for Oldsmobile diesel V8s – died in 1982, Cadillac, being GM’s luxury division, kept their own V8s.  For awhile these were the Northstar engines (1993-2011): all aluminum, shared with Oldsmobile, and capable of running without coolant.  The newest Cadillac V8 is a new design, the Blackwing, a 4.2L twin turbo OHC V8, from 2018-2020.

Moving off from General Motors…

Ford.  Ford eventually phased out its flathead V8 and joined the rest.  Then it came up with a variety of different families and displacements.   302 (5.0L) is probably the most popular, winding up with a carburetor and then EFI in 1979-93 Fox body Mustangs, often with the 5 speed manual (5.0 5 speed).  The 351 can either be a 351 Windsor (same family as the 302) or Cleveland (different family).  For larger engines, there’s the 427, the 428 (including the 428 Cobra Jet), 429 (Cobra Jet and BOSS), and the 460.  Then they phased out the 5.0L in favor of a new design 4.6L, and then went back to 5.0L displacement for a new version of the engine.  To be honest, I’ve never been much of a fan of Mustangs.

Ford V8s – Post Flathead.  Part 1: Y Block (1954-64).  As noted, the Flathead was retired in 1953, replaced with the Y block, which was a more modern OHV design.  The Y blocks have a strange intake setup where the ports are on top of each other rather than side by side.  The lifter design, solid lifters adjusted by the rocker arms, was the most troublesome part of the design.

Part 2:  Windsor/90 Degree (1964 – present).  260, 289, 302, 351W.  Of these the 289 was common in the first Mustangs, and the 302 more common in Fox body Mustangs as the “5.0L”. 

Part 3.  335 Series (1970-75).  351 and 400, with the 351 Cleveland (named after the factory they were made in) the most popular.

Part 4.  FE Series (1958-76).  390, 427, and 428 are the most famous examples.  And the most famous of these is the 428 Cobra Jet, arguably the best street V8 Ford made in the muscle car era (1964-75).

Part 5.  385 Series (1968-75).  429 and 460.  The largest engines Ford made.  These include the Boss 429, the closest thing to a hemi engine Ford made. 

Chrysler.  Small blocks:  318 (5.2L), 340, 360 (5.9L) are the most popular displacements.  The small block Mopar V8 can be recognized by its rear-mounted distributor.  Big blocks: 383, 413, 426, and 440 are the most popular displacements. These include the 440 Six Pack (three two barrel carburetors) and the 426 Hemi.  A 360 will drop in place of a 318, a 440 in place of a 383, but the Hemi heads are so much larger and the engine so much wider, that fitting a Hemi in car that didn’t come with it is not an easy task.  There was actually an earlier Hemi V8 in the 1950s, distinguished by its rear mounted distributor; the 66-71 Hemi has its distributor in the front. 

In 2006 MOPAR resurrected the Hemi as a modern, fuel injected engine in 5.7L and 6.1L (later 6.4L) displacements in the Magnum, Charger R/T, Challenger R/T, and Chrysler 300.  All have two spark plugs per cylinder with individual coils on each cylinder.  I had a 2009 Charger R/T from 2015 to 2020, which had the standard 5.7L Hemi (370 HP).  The SRT8 version, in 6.1L, had 420 HP.  Then they upped the ante with a supercharger, the Hellcat, putting out 700 HP.  Although MOPAR has announced the end of gas engine Chargers and Challengers, the Hellcat V8 is available as a crate engine – should you have the $$$.

Again, the trend seems to be to phase out ICE engines for electric motors, but given the extremely limited recharging infrastructure and length of time necessary to recharge – compared to filling up your gas tank in 5 minutes – the full transition is years down the road, so to speak, if ever.  And crate engines suffice if we need to replace an older V8 with a new one.  LS swaps have become more common and popular among GM owners, as the LS engine is light (all aluminum), reliable, and not only powerful in stock form, but respond well to a richly developed aftermarket. 

New Cars

A quick one, while he’s away.   Err, a quick one before off to a viewing.   I’ll have more to say next week. 

Recently I had an accident, and had to rent a car (paid by the insurance company) while my own car was being fixed.  It was a Ford Fusion, relatively new.   Although I appreciate having something to drive instead of walking, riding a bike, or Ubering everywhere (including New Jersey), some things bugged me.

Let me start with the good things:

1)         Awesome brakes

2)         Decent acceleration

3)         No mechanical issues

Ok, done those.   Here are the features I did not like, relative to my 2009 Dodge Charger R/T, which has over 100k miles on it and isn’t exactly new.

1)         Push button ignition.   Call me Henry Ford, but I prefer putting a KEY into the ignition.   Then again, call me Freud.  

2)         AUX vs. USB.   I use an iPod and Spotify through my Smartphone (Galaxy S6).   If you plug in iPod into a stereo with a USB port, the stereo takes over.  The catch is that the interface is 10x slower than the wheel on the iPod.  Hooking it up through an AUX connector lets you keep control with the iPod.  Moreover, you need the AUX to access Spotify through the cell phone.

Now I’m hearing that some newer cars don’t even have CD players.   HUH?   Ok, that truly sucks.  

As of now, my priority means of listening to music is CD.   I use the iPod and Spotify, but mainly it’s CDs.  I have a vinyl player and if it’s Friday night I might listen to a record, but for the most part it’s CDs.  So I appreciate having a CD player in the dashboard.  

3)         No auto lights.  My Charger has a setting where the headlights come on and off automatically based on light conditions.  The car won’t run down, and the lights will come on when it’s night or a garage.   The Ford didn’t have that.

4)         Horrible dash.  Whoever designed the Fusion dash needs a new job.   Speedo front and center, OK, but the tach?  Right next to the fuel gauge, parallel thereto, really as an afterthought.  An up-down vertical indicator, which is OK for a fuel gauge but sucks as a tach. 

Here’s how that worked out back at Ford:

Manager:          “Dude, where’s the tach?”

Designer:          (Blank stare) “Tach?”

Manager:          (Facepalm) “Give me a damn tachometer.  Figure out what it is and do it.”

5 days later

Designer:          “Here it is.” 

Manager:          (Sees shitty tach but too late to fix it).  (Sigh). 

Charger, Firebirds, Honda Civic, all had round tachs.   No excuses, Ford.  Come on.

Engines 101

These are those strange things under the hood of the car – instead of a squirrel on a treadmill (though on some cars it seems that IS what’s pushing the car so damn slowly!). Very few cars have two (Citroen Deux Chevaux) or three (Geo Metro) cylinders, or as many as 16 (very old Cadillacs, with a V16, and the brand new Bugatti, with a W16). Most have 4, 6, 8, 10, or 12. (I won’t even get into rotary engines, as the Mazda RX-7 and RX-8 are the only cars with this type of engine).

Configuration. Either inline ("straight"), V (e.g. V6 or V8), or horizontally opposed ("flat"). The latter is most common with Volkwagen (flat 4 in the Beetle), Subaru, and Porsche (flat six in the 911). VW has introduced a W configuration (two V’s together) and Bugatti uses it with 16 cylinders to put out 1000 horsepower (!). The Sherman tank of WWII had a 30 cylinder engine consisting of 5 banks of inline 6s in a star formation. WWI and WWII fighter planes and bombers often had a radial engine: the cylinders arranged in a circle facing inward.

V8s. These are the kings of performance. Although Chevrolet had a V8 in 1916, the first commonly used and modified was the Ford flathead, debuting in 1932. It wasn’t until 1948 (Cadillac) and 1949 (Oldsmobile) that Ford had any real competition. And in 1955, Chevrolet released its small-block V8, which took the performance laurels away from Ford.

At Ford and Mopar (Chrysler-Dodge-Plymouth) the company made a common family of V8s, though with separate small- and big-block variants; Ford alone had 4 different series, not counting Lincoln and MEL engines which dropped out in the 60s. Until 1982 each GM division – Chevrolet, Pontiac, Oldsmobile, Buick, and Cadillac – made its own V8s, and Chevrolet, Olds and Buick produced small- and big-block variants.

The top models were the Pontiac Ram Air 400s (I, II, III, IV, and V – the RA II is pictured above) and Super Duty 455 V8s, big block Chevy LS6 454, Buick 455 Stage 1, Olds Rocket 455, Ford 428 Cobrajet, the 426 Hemi and 440 Six Pack made by Mopar, and the AMC 401.

Displacement. Take 4/3 of PI, multiply it by the bore (cylinder diameter) squared, then by the stroke (distance the piston goes up and down the cylinder) and finally by the number of cylinders, and you have the displacement, either in cubic inches (CID) or liters (metric).

Nowadays almost all engines are measured in liters, with CID being talked about only with reference to V8s. Funny, we still use quarts and gallons here in the US, but our soft drinks are sold in 2 liter bottles! Most 4 cylinder engines displace around 1.5-2.5 liters, 6 cylinders between 2.8-4.3, and V8s somewhere from 4.0 all the way up to 8.0. The 6.0L V8 in the newer GTO and Corvette, then has three times the diplacement of the average 4 cylinder engine although it only has twice as many cylinders, and the 7.0L (427 CID) V8 in the Corvette Z06 – with 500 HP on tap – has even more.

Quite simply, the larger the displacement, the more power the engine can put out. Artificial means of introducing more air to the cylinders, such as nitrous oxide injection or super- or turbo-charging, can dramatically increase power and make an otherwise smaller engine act and behave with the power of a larger engine.

Displacement and horsepower gradually increased through the 60s, peaked in the early 70s, then took a nosedive when emissions and fuel economy standards were abruptly imposed by the Federal government, like the cops shutting down a raucous party on noise complaints. After scrambling to master emissions controls, developing EFI systems, and improving ignition systems, the car makers were finally able to satisfy Big Brother that they were doing their job to protect the atmosphere and keep fuel economy decent, and then turned to improving performance again. By the early 90s the horsepower figures (and to a lesser extent, displacements) finally returned to – and then quickly exceeded – those of the 60s.

This can get a bit confusing because some displacements are repeated by different companies. Chevy and Ford both make a 302 (5.0L); Chevy, Pontiac, Buick and Olds all make a 350 (5.7L) – and all 4 are completely different and do not interchange (with the new Dodge Hemi also displacing 5.7L); the same holds true with the 4 divisions’ 400 CID V8s, adding that both Ford and Mopar also make 400 CID V8s; Chevy and Ford both make a 427; Ford and Pontiac both make a 428; and Buick, Olds and Pontiac (B-O-P) all make a 455. AMC shared displacements with Chevy (327), Mopar (360), Ford (390), and Buick (401).

The largest was Cadillac, at 500 CID, but now Chevrolet has crate engines displacing 502, 540, and now 572 cubic inches.

HP vs. Torque. Horsepower is a measure of power over time, but gives a misleading impression of a engine’s street performance. Enthusiasts know to focus on torque, the twisting action which gets a car moving from a dead stop. Just as we prefer to think of 0-60 acceleration vs. top speed, torque is likewise a more relevant measure of real-life daily street driving. In this, V8s tend to shine the brightest. Observe that most 4 cylinder engines, even those with turbo, tend to put out as much torque as HP, whereas a V8 will put out 50% more torque than its level of HP.

Fuel Injection. Until the 50s, all cars were carbureted. A carburetor uses airflow through a venturi to "suck" fuel into an airstream, mixing it through various complicated mechanical subsystems (idle, acceleration, part-throttle, main circuit, cold start up/choke, etc.) to satisfy the engine’s various fuel demands. Carburetors are sized by "barrels" – one, two, and four being the most common, and performance V8s sometimes had six (three two barrels aka "Tri-Power" or "Six Pack") or eight ("dual quads" – e.g. the 426 Hemi).

By the 80s, carburetors were being electronically controlled but also phased out. Nowadays the only gas engines with carburetors are on lawn mowers, motorcycles, and other small devices – and vintage muscle cars. The famous Rochester QuadraJet (GM), Carter AFB (Mopar), and Holley (aftermarket) 4-barrel carburetors are still sold in various forms today for enthusiasts with older cars.

In the 50s mechanical fuel injection made its debut. Patterned somewhat off diesel systems, they appeared on Mercedes, Corvettes, and a handful of other cars. It was never popular and most mechanics had no idea how to service them. Many owners switched over to carburetors out of sheer frustration.

Bendix had attempted electronic fuel injection (EFI) in the 50s, only to be hampered by vacuum tube computer technology. They sold the rights to Bosch, which was able to make EFI a practical reality in the late 60s when transistors – and later integrated circuits – vastly improved computers. VW came out with the first EFI in 1968, Mercedes followed soon after in 1972, Cadillac in 1975, and in the early 80s Detroit and Japan began switching over. By the 90s the transition was complete, even on trucks.

Saabs, Volvos, VWs, Audis and Porsches often use a strange form of EFI called CIS (continuous injection system) wherein the injectors - one for each cylinder - are always open, and engine speed is controlled by increasing the fuel pressure. As odd as it sounds, it actually works pretty well.

The earlier form of EFI on US and Japanese cars was throttle body injection (TBI), which has a device of the same size and location as a carburetor, sitting on top of the intake manifold, with an injector or two squirting fuel for all cylinders. It's not particularly fancy or effective, but it's better than a carburetor. TBI is an intermittent system with engine speed changed by increasing or decreasing the pulsewidth of the injectors - how long they stay on spraying fuel before shutting closed again; the shortest pulsewidth at idle, increasing up to wide open throttle (WOT).

The usual EFI system these days - and used on all high performance applications - is port fuel injection, with intermittent injectors, one for each cylinder. Some are sequential port (injector fires for its cylinder on the intake stroke) others are batch fire (injectors fire in pairs), though like CIS, the batch fire system works surprisingly well in practice, with no noticeable difference in performance vs. a sequential port system.

The latest wrinkle in EFI development is cylinder deactivation, whereby certain cylinders are turned off at idle and part throttle and the full engine only turned on for full throttle – saving fuel without a noticeable decrease in power. Cadillac tried that in 1982 with its 8-6-4 engine, but the technology at the time was not good enough to do justice to the concept, which only recently became practical.

OHV vs. OHC. Overhead valve means the camshaft, which opens and closes the valves, is located in the engine block and uses pushrods and rocker arms to open the valves. Overhead cam means the camshaft is located on top of the cylinder head and operates on the valves directly or through followers. The major deal with OHC is that such engines are believed to breathe better – because they usually have four, instead of two, valves per cylinder – and thus offer more top end horsepower. Certainly many of the performance snob journalists at Motor Trend and similar magazines consider OHV to be obsolete. Yet GM and Mopar have proved with their more recent OHV V8s and V10s that OHC is NOT the only way to make substantial power, and OHV is by no means obsolete.

 There’s a lot going on under the hood, but it’s all fairly simple. And there IS a difference between a 4 cylinder and a V8, as I know every time I step on the gas...and fill up at the Sunoco station.