E58 400 plus HP Dart sport build

how much initial timing do you have on the engine?

I know you have a thumpr cam is it the small, mid or large one. If someone told you you would get 13in of vacuum with the mid or large one, yeah not gonna happen at a typical idle level. The large one is 240+ at .050, not "idle" or vacuum friendly.

Have fun with it. Good to read it is broken in and running strong.