[Steeveedee]

I had a '64 Impala convertible with the SHP 327 (300HP). It had 2-1/2" pipes from the manifolds to the mufflers and 1-7/8" pipes all the way out to the back. I could pull 6 grand out of it, no problem. If you look around, you can find a video where a couple of guys hammer a set of headers full of an unbelievable number of dents without any reduction of HP on a dyno. I'll go look at my truck tomorrow (stock BBC) and see what size the exhaust pipes are. I know that they aren't all that big.