i kinda have the same problem.. my grandfather rebuild my 72 350 and put a rv cam in it cuse it was in his c-10 way back when. it dont realy have a problem geting the tires to burn it just has a problem with choke.. ive got no choke on it so when i let off... the engine bogs way down and if im not carefull the engine will flud its self. ive got alot of proformance parts as well as builstien suspention and later bars to help with hookup. just thought ide put my 2 cents in. also with the 79s is i think you have either a 2.54 or a 2.70 rounda bout gears in that thing. that by its self will make it hard to burn the tires. put in some 3.73 gears and youd might wanta invest in ruber. o.. and your cam lobe on the 7th cylinder might be worn all the way down cuse thats where alot of pressure is put on the cam. so u might be runin on 7. thats what my grandpa said any ways.

 

I have a 79 and they guy who owned it before me replaced the rear end with 2.8s or so. I don't think it comes stock with the 2.8. it comes stock with posi traction so I think it has a 3.43 at least. As for the cam you need to do a compression test, and then take it from there.