What Cam would you suggest with this

for a good healthy sounding camshaft that is not so radical you can pop corn on, go with the specs for a stock 340 grind cam shaft for an automatic its like a .424 / .444 .
Sounds good at idle, 1200-5500rpm range for pulling and not so radical that you need to change your rocker gear.
I would however invest in a new set of lifter springs. They get weak over time and a stock set from an auto parts store are cheap like $50.00 usd.

Joe