Vacuum is pretty low for that cam in your application.
I built the same exact engine many years ago for my 1970 Roadrunner, 906 heads, flat top pistons, and steel shim head gasket with the Mopar 284/484 cam. It idled pretty good, with around 11-12" vacuum at idle speed. I drove and raced that engine for several years before replacing it with a 440 engine using the larger 509" lift Purple Shaft cam.....Cliff
