Neil Mc

I'm helping a buddy with a ls powered ratrod . Quick rundown on the car is it had a stock 5.3 with a china gt45. Ran good with this setup. Blew a head gasket and hurt a piston a few weeks ago so we put a 4.8 in and used a LS9 cam we were saving for a 6.0 that was going in another car. Now the car is a dog until 3500 rpm and then turns on hard . We are running a stock converter which worked fine in original setup. It also has the big 18 wheeler style tires so we cant really go much looser with converter or it will spin tires. So my question is should we jerk the ls9 cam and go back stock cam , try a stock ls1 cam, or?????
Pretty much stuck as far as the tires ...could maybe go a little looser on converter but not much because it was already on the edge as far as traction.