Q&A

Mailbag: Tips for Supercharging a 454 Engine

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Q: My Pro Street 1967 Chevy El Camino is powered by a 454, bored .030″ over. The engine has a Holley 750 cfm carb, an Edelbrock RPM Air Gap intake, 8.5:1 flat top pistons, World Merlin oval port heads, a Mallory Unilite distributor with a HyFire 6AL box, a COMP Cams Magnum hydraulic cam, and shorty headers. It also has a TH-350 transmission.

I’d like to add a 177 c.i.d. supercharger. Do I need forged pistons, or a special carburetor? I just want to get the job done right the first time without a lot of trial error.

A: If you mostly want the blower for looks and mild performance for the street, your current pistons should be fine. If you’re going to run serious boost at the strip, though, you’ll need the extra durability of forged pistons, plus some top-quality piston rings.

You don’t need a different carb, but you will need to enrich the fuel mixture to prevent leaning out and detonation. We also recommend a more aggressive camshaft. Yours has 110° of lobe separation, but you’ll want around 114°, along with a longer and higher exhaust cycle. Don’t worry—the supercharger will help smooth out the rougher idle from such a radical cam.

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One Comment

  1. If using a Holley or Holley type carb that uses a powervalve, it will need to be boost referenced to prevent a lean situation, which could seriously damage your engine. You can modify your own carb, or you could buy one that is already adapted to run on a draw though blower.

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