Here's my take: 355cid, fairly big heads, long duration cam, tunnel ram, 4-speed, heavy car = a real pig out of the hole. Your gonna need a LOT more gear to get it moving and keep in an rpm range where it's happy. 7500rpm plus would be my guess. Personally I'd ditch the tunnel ram and go with a good single carb race manifold, one 750 or 800 cfm should be plenty, race gas, 5.13 or more gear. I'll bet you could run e85, but getting it right will be a pain, especially with 2 carbs......jmo
Johnny