Thread: My Chevy 355 has little real power - looking for suggestion on CAM change

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Originally Posted by techinspector1

Combustion chamber volume?
Head gasket thickness?
Piston crown to block deck dimension?
Volume in the piston eyebrows?
Cylinder bore?
Cylinder head intake port volume?
180 or 360 manifold?
Carb spacer?
Cam installed on centerline or advanced/retarded?
Initial spark lead at the crank?
Total advance? All in at what rpm?

68cc combustion chamber volume
Head gasket thickness is .041 thick (felpro 1003)
Eyebrow volume? can't say I know.
Cyliner bore is .010 over
Intake port volume 184cc . Intake has apparently huge plenum volume. Holley 300-36 intake.
Yes plastic carb spacer 3/4"
Cam is installed on centerline
I don't know about initial spark lead at crank - I don't know what that is
Total advance is 36 degrees at 3000rpm. Lightest springs using a curve kit. Static timing set at 15degrees with no pinging evident at any rpm.
Block hugger headers with 2.5" exhaust 2 into 1-3" pipe then out. Using flowmaster super 40 (one).
180 or 360 manifold? not sure what that means. The plenum has a split rib where the carb base goes onto the manifold.

Does that help? I plan to call one (or some) of the cam companies to help, but I want to be sure that is my problem.

I agree I may have to re-carb. This Holley 750 is new (from a friend who did not use it stil in box). THe systemax kit recommends a 750, that is why I am using it. I don't know enough about carbs (I know some, not a ton) to know if only shrinking the carb CFM will move the torque curve down low enough. My guess is not enough, it is a bigger issue than just that.

More cam details:

234/244 both at .050" lift of .488"/.510"
1.5 ratio
lobe centerline 107
love sep angle 112
All specs from Holley/Lunati website on my cam

Pic of the top of the pistons when refreshing the engine this last winter: