get rid of the holley 750 dp and go with a proform 650 dp or even vaccuum secondary. You'll pick up at least 20hps if your using a standard holley 750 dp. A 650 is plenty for the 306 .
You beat me to it flynbrd! That's way too much carb, Depending on cam (ie. max RPM's) you probably only need a 600cfm. http://www.4secondsflat.com/Carb_CFM_Calculator.html With alumnum heads you should be around 85-89 VE Also whats the compression ratio?
Dude. You should smear your friends 5.0 fairly easily. My set up as of several years ago: Original 302 shortblock idling at about 3 PSI oil pressure Ported 69 Windsor heads, Big valves "Big" hyd flat tappet cam with .510/.515 lift. 230/235 Dur... Twisted Torker single plane... With 625 demon vac secondary's... (Bad combo I know) C4 with absolutely factory stall (1800 RPM or so) 8" peg leg with 4.11s street tires. Beat my friends 89 5.0 notchback Stang with 5-Speed cold air intake, E Cam, and 3.55 gears by about a car and a half. I started a little behind and was running away from him at the other end. A few years later I made these changes to my car: Air Gap dual plane intake with Holley 650 DP. (WAY Better combo) 9" rear 3.70s with Detroit locker. Ditched C4 for a T-5. Oh, and now idling at 2 PSI oil pressure Raced a similar equipped 88 5.0 5-speed and beat him so bad I thought he broke his car
