[olddog]

If your exhaust is two completely seperate pipes, an "H" or an "X" type cross over would help quite a bit. Only one cylinder is pushing high pressure out the exhaust at a time. This will allow each cylinder to exhale through both sides. The "X" is supposed to improve the scavaging affect by creating a ventury, but it gives a higher pitched sound.

Ditto on the 650 cfm carb. A 350 cid at 90% effeciency would have to turn over 8000 rpm to suck in 750 cfm. No way your heads and cam could be up to 90% at those rpm or your hp would have peaked in that rpm range.

Figuring 100% effeciency at 6000 rpm and you would only be pulling in a little over 600 cfm.