I have a Torker 340 on my 340. The motor seems to run out of steam at 6200-6300. Would a RPM air gap do any better? I think the Holley DP is an 850. And yes, with that manifold and the big cam the motor doesn't really wake up until around 2500-3000.
No, reason being, the engine is running out of steam due to the camshaft. The intake is free flowing enuff to go higher.
As I am kicking around the idea of building a 408/416 from an old 360 block I have maybe getting the RPM now (to be used on the stroker build) would be a good idea.