I ain't got no traction satisfaction !!!

[Green Machine]

Basicly stock 1971 C20 LWB body and chassis, turbo 350, 2000 stall, 3.54 Dana posi an a healthy 383. I know I need more rear tire, but want to retain the sleeper look. Have 245/75 R16 8 bolt front and back now. I can get a pair of painted 8 inch 8 bolt wheels that take the stock hubcaps and go to a 265/70 R16 tire. Or maybe a little more, any suggestions ? I want to stay about same tire height.

The truck pretty much spins both tires all the way through first gear and just catches traction just before it shifts at about 5500 rpm. Would some half ton rear springs help, maybe some half ton front springs too ? Need to get some weight transfer going on or something. I can still beat most everyone out of the hole while spinning the tires, but if I could hook up, that would be much better !!! Any thoughts ? Had it to the track twice this summer, runs about 9.50 in the 1/8, pretty good I think for a 4200 lb truck and no traction.

Any thoughts appreciated - Thanks.