it's called 3.23 gears man. They don't help ya get out the hole very good.

I took my 04 ecsb full streetweight which was just above 5300lbs and ran a 15.9 as well. I forget the mph. Only differance was i had 3.43 gears and a pegleg which didn't matter cause i got it to dead hook up till i did lt's on just the pegleg.

 

Nelson is goingto have fun tuning that turbo for you!!