"With 3.08 :: 1 gears in the diff you can’t use OD at all. Your engine rpm at 60 mph would be 1600 rpm. Most gas engines barely make power down that low. You could use the 700 R4 if you change your gears to 3.42, 3.73, 4.11, 4.56, 4.88, 5.12 or 5.30."
Looks like I will have to up the diff to 3.42 or 3.73. He likes the 700 R4, why?
Then ask him to explain the 1991+ Caprice with an anemic 305ci, 4L60E, and a 3.08 rear along with 27" tall tires back when the national speed limit was still 55mph? Your combination will be fine even with a .67 overdrive.
The 2004R is easier to adapt to a Pontiac, and has a better gear set than the 700R4 (some don't like the wide 1st to 2nd gear drop of the 700R4). And when upgraded, they're about the same strength.
Honestly, if a trans builder made that statement to me, I'd be looking for another builder.
I agree regarding finding a new tranny man. Check the rpm of any modern vehicle at highway speed.
Last edited by Bronze Bird; 02/18/1910:32 PM.
I'm a hobbyist. Not a professional. Don't be hatin'!
