my experience with this cam (ran it in my 408 for some years now): performance significantly improved with 1.6 rockers, dropped 2 tenth on the quartermile. I did not notice any impact on the rpm range - run mine to 6500 rpm.
What vacuum is necessary for the efi? I had trouble with the brake booster, changed to manual. If i remember correctly the best vacuum was around 10 in/hg with my combination.
I think the best bet is to talk to experienced builder. Maybe a custom grind with bigger LSA is better suited for your engine.
Michael
