I'm on the fence on this one....If it were my decision I'd really have to ask myself how serious you were about tracking the car and running E85. Next big question would be are you going to be using drag radial or slicks...

I have a very similar setup to yours and on E85 without and IC and without P&P head I put down 330whp/400wtq. When talking with Dave at TEP I had plans of pushing my setup to the 350whp and that's when he led me towards running the 7/8" setup.