I bought this engine a while back and I think it has WAY to much cam. Here is what the PO posted about it few years back:

"specs:
350 long block core from Napa
Hedman Exhaust Headers (very tight fit beware)
New alum. water pump - Mondello.
New Edlebrock 3711 performer intake manifold- Mondello
New adjustable valvetrain on #8 heads – Mondello
New Hyd. Cam Jm18-20, .488 IN, .496EX, 260/266 duration- Mondello
New JM 830 Annular Carburetor (vacuum secondary) – Mondello
all except headers Mondello recommended

I've put an Q-Jet on it, converted to HEI, tuned it the best I can and it runs like S**t, not enough vacuum (8"), and too rowdy for me. What cam would you suggest I go with and should I change anything else. I'd really like to go as close to stock as possible because I'm sure it's a low compression engine. Thanks

 

Any idea what pistons were in the short block?
If they're the big dish piston, couple that with the #8 heads you may have about 7.5:1 compression.
That cam isn't too big for an 8.5:1 or better small block. You may have other issues.

 

It has the big dish pistons.