How much more horsepower than the edelbrock will an 068 pump out in a 400+.060, with 670 heads, Carter 625AFB, stock log manifolds, 3.42 gear, TH350? Maybe 10 or 15hp? Or is it more like 50hp. i.e. is it worth the change? Engine runs pretty good with the edelbrock. No pinging, good idle, good low end torque.

Edelbrock
204/214 duration @ .050 lift
.420/.442 lift at valve
110 Deg lobe separation angle


068
212/225
.408/.407
116 Deg

with the 068 you will lose horsepower, but you will win a bit of torque.

sportsman

In my opinion, the switch would not make much difference. If you want more HP you need a bigger carb.
Jim

I would go with a 750 Q Jet or RPM replacement carb, a 262 or 268 Comp Cams Grind

1. 218/224 462/470 110
2. 224/230 477/480 110

You will need a stout cam with those heads and CR you will be running. A decent overlap/lift will reduce some of that compression.

I would definately swap the carb. The cam, either way will not make a noticable improvement or difference.

You want to run a 110 LSA and a higher lift for CR and streetability. IMO

Thanks for the input. I'm new to hot rodding engines...but I've been reading about this stuff since I was a kid.

I guess I'll leave the cam alone (especially since the engine is back in the car now).

Maybe rather than cam, I should port the exhaust on the 670 heads since I'm running more than .400 lift. Any comments on this?

I might try a bigger carb, but the CFM calculations assuming 90% volumetric efficiency tell me 600CFM is enough. So, I'm a little confused about this, but I don't know of anybody running a carb that small on a 400 plus cube motor.

The car runs pretty good now, so maybe I should just leave it alone.

Definately no on the exhaust side..Intake only. 670, and any Pontiac head except for the RAIV.