You are on the right track. Measure the cam. If you can get a degree wheel, also check the opening and closing of the intake valve. While you are at it, check the slack on the timing chain the same way that TOHCan told Yellowbird. Let us know what you find, and we'll do our best to put together a solution that works good with what you already have.

Two ideas come to mind. The sputter at 4200 might be ignition related, either "points bounce" - they are set too wide (dwell too long) or some other timing related issue like broken mechanical advance spring or springs. I can't imagine the cam causing such a narrow power band, even on that engine.

The other idea is going to sound like a broken record: Advance the cam. With the duration of the 2801 nearly the same as the 068 Ram Air cam, the intake valve is closing later than it should for your engine/head combination. That's what's taking away the low-end torque. And since you have such small valves, you are not getting the power back at higher RPM.

I know you must work with what you have. I may have been a little too harsh about my critique of the #11 heads, but that's only because there are better heads.

Q

PS: I will gladly stop by in Munich next time I am in Germany. I will also be looking for someone in Heidelberg. Maybe a trip along the Romantische Strasse in a 1969 Firebird ...