How many racers made the switch and what did you really gain?
I've heard all the rumors and speculation......who's got the hard numbers?

It's been a long winter.

Why Vic; don't you believe me?

I never made a back-to-back comparison, but it was tested and documented in the '70's that a 904 will be about .15 faster than a 727, all else being equal (i.e." converter, low gear, etc.) I always ran a 727 in my bracket Challeneger. But when I went class racing in IHRA Stock, a 727 was never considered because of the occasional heads-up runs.

I made the switch back in 1993,,,

removed a 727 with a turbo action 4400xxsm converter which was set up for the car.

and put in 3800 series converter with a 904 which was probably a little too tight for the car.

i did pick up approximately .15 and 2 mph.

A ss racer trans builder said he gained .15 when you look at the drum sizes and weights your spining and it's lighter even with the BB conversion so??