[rfmaster]

Originally Posted by RandyP

Be careful with the cam choice, too much cam is bad for a TBI system. My cam is .450 Intake /.460 Exhaust and sucks badly for the TBI. Basically it is not creating enough vacuum at lower RPM.

I would have to partially disagree with that statement. Valve lift is not an issue it is the cam duration and overlap that affect idle vacuum. In my latest project (HOT 383) I have used 0.500/0.510 lift cam with 212/220 duration at 0.050 with LSA 114 deg. 383 is TBI injected and it idles at about 725-750 with 16-18 in-Hg.

Back to discussion
400+ HP from any SBC (carb or FI) will require careful parts selection and engine work. At these power levels little things begin to matter and the money drain increases exponentially. FWIW, if I may ask why do you need 400HP in a street truck?? Your current TBI engine LO5 is about 180 to 190 HP on a good day. As it was mentioned Vortec heads, correctly selected cam, matching intake, dual exhaust, and with custom tuned BBC TBI can bring your engine close to about 300 HP with a reasonable investment. The next 100 HP will take a lot more money....

//RF