Is 7/8" enough slip yoke travel before it bottoms out?
1970 440 4speed challenger with b-body dana and Hotchkis springs. I am using the same driveshaft when I had a 8 3/4....45 1/2" long.
I know the Dana should have a 1" shorter driveshaft.

hi
should be fine , i normaly shoot for 1"

I was taught with the car on the ground with the weight on the tires and suspension to slide the yoke all the way in until it bottomed out and then slide it back towards the rear end 3/4 inch for making the driveshaft length correct, that has worked very well for me

Sounds good to me.

Is that 7/8 loaded? If so that is plenty & I like 5/8-3/4. (depends of the intent use).

Yes loaded. I was kind of surprised the same driveshaft from the 8 3/4 fits.

It is probably more than enough, maybe too much. Instead of more than enough, I prefer just enough. It makes for a more stable yoke.

The 1" clearance is a blanket rule to cover everything including trucks. They sit high, lots of clearance and are often loaded, less clearance.

If a car sits low and loaded. The clearance of 1" will never come close to bottoming out. It will only pull out as the suspension droops. It may move forward less than 1/4".

this brings up the question of which seal is on the tailshaft, the shielded one, or the cheapo one without the big, rubber end.
and, as always, i have done the "bottom, then pull out 3/4", but i don't remember if that was with, or without, the shielded seal in place.
refresh my memory please !

Without, & yes you are (loosing) it! (it'll get worse)

Do the math.

it's to bad they don't show how far out the output shaft sticks out from the tail shaft housing seal

On my 2 original dana cars one the bulb seal runs 1/8 from end of bulb to driveshaft yoke, the other is 1/4. It works out to about an inch out. Do not make it 1" out from a bulb type seal, that is wrong. 3/4 to 1" from a flat seal. Things move more than you think sometimes, and too far in could maybe knock the plug out of the yoke.

I'm doing the same except with stock HD springs.....5 yrs, 6000 miles, no problems
jess

it's a good thing you are here john ! thanks !