Not as Hipo as it sounds. What's up?

I think 2 things

1 compression ratio

2 the 2 into one exhaust.

MANY years ago I had a 440 with an unknown "freebie" solid cam, measured at "somewhere" over .5 lift and "around" 300* duration. Thing ran like a bomb an pulled clear up to 7K

I put the engine in a '64 Dodge, and didn't have headers, only the "log" manifolds and dual exhaust.

THAT THING WAS SLOWER than a stock 335 hp 383!!!