727 vs 904
727’s also backed /6 & 318’s.
Took me a minute to get it. Lol. If I am right going s6 to v8 and using a v8 904 I do not have to cut the driveshaft. Putting an 8 3/4 rear in place of the 7 1/4 I have to change the u joint to a 7260/7290. Am I close? Thanks.
Question 1, correct
Q2; It’s not the U joint that’s an issue. IF there are two different U joints sizes between the rear and drive shaft, several companies make U joints that are half 7260 & half 7290. Check Mancini Racing.
Going from a 727 to a 904, the holes that slide into the transmission are splined different. The yokes can come in both U joint sizes.
Each MoPar rear has a different length nose, the driveshaft has to be cut down.
Also, the 727 & 904 are different lengths.
Not all driveshaft shops will tell you measure the driveshaft length from the flat of the yoke on the rear to the flat of the transmission and also the amount the transmissions shaft comes out of the rear, but generally that’s how it’s done. Sometimes they want you to slide in the yoke and pull it out 1-1-1/2 inches and measure to that mid point of the yokes U joint hole.
This is all easy and all you need is a bud to hold the cam ape measure at 1 point. You read the number and fraction.