Quote:
Originally Posted by 67 cst swb
Both your newer vehicles have OverDrive Trans add another demension to the equation.
|
Yes, the Sierra has a 4L60 trans which has a 0.67:1 final ratio, where as these old trucks with stock trannys (manual or auto) have a final drive ratio of 1:1
The OD reduces the final gearing about 33%.
My 67 with a 350, 700R4, and 3.73 will spin about 21-2200 rpm @ 65-70 mph.
If this truck really is just a play toy, I'd leave what you've got in there. I'm assuming your adding the supercharger for more fun and power? Putting in higher gears is going to kill your launch time and make the money you've spent on the supercharger kinda pointless?
I'd put in a good set of 3.73 if your truck doesn't have them already (that seems a little unclear at the moment?)