Ditto on the power valve number. Big cam? Get LOW on the PV number. I'd be worried 5.5 is to high!
Measure your vacuum at idle, wouldn't be surprised if you had near zero or only 2 or 3 with a BIG cam. If so, even 5.5 will be to big. Try advancing your BASE timing to increase idle vacuum. BIG cams like lots of base timing. You still want to be careful not to pull TO MUCH mechanical total advance timing so you may have to adjust that. But base timing is critical to a "decent" idle speed with lumpy cam.
...wish I had a couple of 600 Holley with power valves. Mine are 660 full blown drag race RADICAL Holleys. I gave up trying to get a "decent" idle, it's just "OK". Hold on if you nail it though, it WILL launch!