Thread: 400 Small Block

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My grandmother past away leaving me a 1972 chevy Impala with a 400 small block. The car is currently a dog. Is this worth messing with to get more power from the motor as in new carb / manifold and headers or should I leave it be and just put a chrome dress up package on it?

Try posting your question in the chev forum

Jct400SB; Those were Great cars, my father had one and I wish I had it today. I think It's well worth hanging on to and fixing up. Go with the polished aluminum valve covers though, the chrome ones like to leak alot and the aluminum one's seal better. that SB 400 is a great motor have lots of fun with it.


~ Vegas ~

Thanks for the input. Does anyone know if this is a 4 bo0lt main or the 2 bolt? Is there anyother way to tell without pulling the oil pan?

don't quote me on this, but if i'm not mistaken, on a 400, there where 3 freeze plugs on the side of the 4-bolt model, and 2 and a 2 bolt, once again, not positive, but seem to remember reading that somewhere

yes you are right 3 frezze plugs are the 4 bolt main the 2 freeze plugs are the 2 bolt mains.i heard that a 2 bolt is better for building because they are alot stronger that a 4 bolt down in the webbings

The 400 is a good engine for torque.

You would be surprised what a difference freeing up the exhaust, adding a dual plane intake/4bbl carb, and bumping the timing up will do. Just keep in mind its a heavy car with a stock engine that doesn't rev too high, so torque is what you should go for.

Change the diff gears and you'll be giving a lot of people a good run with your boat

There used to be a local guy with a 1970 455 Buick stationwagon that got into the low 14's with just bolt ons and tuning..... It was funny watching him shut down Mustangs!

I wouldnt be consirned about wheather its a 2 or 4 bolt main