Chevy Small Block Evolution - Performance Q&A

Kevin McClelland Feb 1, 2010 0 Comment(s)

The Life Of A Small-Block
The small-block has now been around for 45 years. Yes, it has been through four generations of design, each with its own benefits for specific projects. The old-school group will always be a Gen I small-block crowd-that's a lot of our readers-who still enjoy the regular 355 and 383 builds that fit their comfort level and budget. The pieces for the Gen I small-blocks are plentiful, and you can build decent, reliable power at decent prices.

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Then we move to the Gen II folks who love the early small-blocks but really appreciate the upgrades in the fuel injection and cooling system and parts interchangeability. Good usable cores are plentiful in the wrecking yards, waiting for either a stock rebuild or a warmed-over build.

The Gen III is a total redesign of your familiar small-block. All-aluminum, fuel-injected, a different firing order, nothing interchanged (almost), the familiar engine mounts are gone, and our standard transmissions don't bolt up. This was a real game changer back in '97. Look at the power these engines ended up with out of the LS6-the final LS6 produced a whopping 405 hp SAE through cats and production exhaust!

Just when you thought it couldn't get any better, The General comes along with the Gen IV small-block. The LS2 first saw the light of day in the '05 C-6 Corvette. This was the base engine producing 400 hp and knocking down a mid-20 mpg average over four years. My dad picked his up from the plant in Bowling Green and has never reset the mpg average. It's in the high 24s, and I guarantee you he drives his Vette!

The Gen IVs are the latest in technology, with the new ZR1 Corvette LS9 engine producing 638 hp and 604 lb-ft of torque! This is the most outrageous production engine GM has ever produced. With the family including LS2, LS3, L76, LS4, L92, LS7, LS9, and LSA, from '04 on, that's quite a choice. Many young people out there only know the Gen III engines and up for muscle cars. The aftermarket has embraced the LS engine architecture like the parts manufacturers did back in '55. You can have any flavor of LS engine for your performance level.

So figure out where you are comfortable and pick your engine. We'll support any of the above builds and won't walk away from any of them. All we see above is big power at affordable prices, so pick your poison.

Wheel Deal
Q: I use my '72 Chevy Nova for drag racing. The stock front chassis was removed and replaced with an '85 Pontiac Fiero chassis to reduce front-end weight. I have a problem with the front rotors' bolt pattern. The Pontiac Fiero hub wheel bolt pattern is different from the Chevrolet's. We had to redrill the Fiero rotors for our two front Chevrolet wheels. The new bolt pattern is near the end of the Fiero rotor.

I would like to use Pontiac Fiero wheels to avoid redrilling the Pontiac hub will be eliminated. I have called several wheel companies, but they don't have any Pontiac Fiero wheels 3.5 to 4 inches wide. The minimum width available is 6 inches. Do you know of a company that supplies 3.5- to 4-inch aluminum wheels for a Pontiac Fiero? Who can supply a Pontiac Fiero front disc rotor with a Chevrolet bolt pattern on a hub with no bolt pattern that fits a Pontiac? My main objective is to have a set of wheels and rotors that fit together without drilling the rotors to get the wheels to fit using the Fiero spindles. I appreciate your help on this issue.
Sammie Taylor, Jr.
Moncks Corner, SC

A: Interesting conversion! Nice job lightening up the front of your Nova. Weight costs money no matter how you do it. Finding a set of skinnies for your 5x100mm bolt circle is a little tougher than you'd imagine. Harder than finding wheels is locating rotors for the Fiero spindles that are fitted with a 43/4-inch bolt circle. We found a couple of sets of wheels, but let's take a look at your options.

Not knowing how much material you have to work with, have you considered going with a 41/2-inch bolt circle instead of pushing it out to the standard 43/4-inch Chevy pattern? If you're at the edge of the material with the 43/4-inch, maybe the 1/4-inch difference will get you there. This would be the cheapest option. Then you could run standard 41/2-bolt-circle wheels, which are plentiful from either Ford or Chrysler vehicles.

As for wheels, Weld Racing offers a wheel, PN 766-50412, in its Import Drag line, it's a 15x3.5, has 1.75 inches of backspacing, and comes with the Fiero 5x100mm bolt circle. You can also check out Bogart Racing Wheels, which can build you a set of wheels to any specification; also very nice pieces, but they are racing specific and have a nice price tag to go with them.

Look at both options and choose which works best for you. Good luck with your Nova and remember to keep safety in mind when playing with the rotors and redrilling. There's nothing worse than a too loose front wheel at speed!

Sources:, weldracing.comSources:,




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