As others have said, 7000 rpm is about peak, and I only ran to about 72-7400 through the lights but it was dropping off. I ran an LD340 modified same as yours and a very similar engine combo except bigger flat tappet cam. 5.57 gear (car was an E-body, so heavier). Switched to a single plane and picked up 2 tenths, but you are playing within the rules so that's out. Kept that LD340 on the shelf for a long time before I was willing to part with it because it's a great intake!