Car in question is a 67 Chevy II box Nova. Approx weight is 2600-2800 lbs. Sm block chevy motor (about 650 hp) TH 400 trans, 9" rear with 5.13 gears. The tires are 32 x 14 x 15. I think this tire is way too big. He upgraded the rear from 4.56's to the 5.13's this winter to compensate for the large tire. The slicks are old and I am thinking that they are just dried out and not useful anymore.
We went to MIR yesterday and his best before was 11.35 @ 120. He then ran 11.33 at 120.??, then 11.001 @ 124 and his best of the day was 10.96 @ 124.8.
He knows that he needs new tires. The question is, should he keep with that size tire and gear or should he go smaller with both. With the racing I have done and watched I am thinking he should go with a smaller gear and tire. He is shifting right around 7000 and crossing the traps between 7200-7300. Personally I think that its taking alot of HP to turn those big *** tires. Wouldn't be be much more efficient to come down to a 4.56 gear and a 28" tire??
I know this isint an LS1 question but any help on this is greatly appreciated. If there is any info I am leaving out just ask and I will try to find the answer.