[radz28]

I'm not sure there would be much of a benefit to go from the 3.45s to 3.70s. My brother and I had pretty much the same set-ups on our cars (Yank SS4000 converter for him and an SS3800 for me, same lids, tunes, and he actually had QTP LTs on his car (I haven't run since I've reinstalled mine) and with his 3.73s to my 3.23s, we've run pretty much the same 60's; in fact, the same. His best run on the OEM manifolds and Y-pipe wasn't really any better. Our cars both made within ten horsepower of each other, so that's about as far a comparison I could make, which is what leads me to the opinion above.

If you want a benefit, you'd have to get drastic and go with a 4-series gear probably, and deal with more noise, lower mileage, and more wear-and-tear.

I don't think the GXP is going to be a lot slower than an SS with the same trannies, so whichever is tested first, I think, will represent the other pretty closely, IMHO.