+1 on the 305's with CNC'd chambers, I have them on my NA 524 in a Velocity 280 and I run 90 with 4 adults and full fuel. I did do gasket match and port work myself. I f you check the flow on the fully CNC'd 315's they are better than anything from anyone else. they flow better than other's 350's with better velocity for more low end torque. I've had 9 adults and several coolers with a 30p Bravo prop and still got on plane without tabs.

Are you at sea level? I hear it makes a great deal of difference. And so you guys think with a blown 509 I should go that small and steer away from 325cc heads?

What did you do with the fuel injection to compensate for the extra boost which requires extra fuel, it sounds like the motor is very lean.

I've got 80lbs injectors A1000 fuel pump running Holley commander 950 I have wide band set at 12.1 afr

I think I'm about 800-900 ft above sea level on Northern Lake Huron. You need to look at the flow of the AFR 315's and compare them to the others, Chevy High Performance Magazine did a side by side dyno run with all the majors and the smaller AFR's out flowed and out performed all the others. If you don't believe me just talk to Bob Madera he's one of the best and he swears by the AFR 305/315's.

Fixx brings up a real important point with a blower you must consider the cam overlap and duration, what is the duration at .050, remember you want to keep the boost in the cyl. not blow it though!, the exhaust scavanging design of NA cam not as important on a blower motor, I know it ran on the M1 unit, but the M3 could be blowing the extra air right on through. Just a thought! I run 315 heads seem to flow great in my bbc.

just pickup my 509s yesterday from the machine shop, AFR 335 marine coated heads, 691 crane roller, with 3.3 whipples, dustin at whipple recomended I use them..

A Procharged engine uses a different cam than a Roots or Whipple engine.

tcwcar,

What is your max WOT RPM target with your 509?

Bob

I turn my 509 500hp cam, 5600 @6psi with a M3 thru their ****ty carb box 950 prosystems carb, 80.4 GPS 253 checkmate, no tuning as of yet...building EFI for next year...