Quote:

Obviously you have hydraulic lifters..
If original Mopar OE stockers 5K or a little over is all you will get...

Just my $0.02...



My 383 had a 292/509 old school purple shaft with stock springs and rockers, and Summit hyd lifters. It would pull hard up to 7200 and would keep going if I didn't shift or back off.

Previous owner used it for bracket racing and would hold it to 8000 on the shifts.

When I first installed the engine it would fall flat at about 4800-5000, mine ended up being a bad carburetor. I switched from the Holley it came with to a new Eddy 750 and wow, that woke it up.

Latter added the tunnel ram and a second Eddy 750 and I couldn't stop giggling.

But it seems the OP had determined its not a fuel issue.