i finally went a head and bought and modified a edelbrock sp-2p 318 to fit on my 1965 barracuda ...it is nicer than the factory 2bbl but didn't help the performance as much as i hoped but it asking a lot lot form a engine with 90lbs of compression
sp2p's are economy mpg manifolds. Not much good for performance. the runner sizes are pretty small. Better off with a performer or something like a dual plane with larger runners on it.