[Schurkey]

I guess I don't understand what's going on.

You're mounting the engine with a mid-plate. This pushes the transmission rearward by the thickness of that mid-plate.

The transmission has a slip-yoke at the rear for the driveshaft connection. The rearward transmission causes the splines to engage more deeply.

None of which changes the location of the axle. The axle doesn't move when the transmission is crammed rearward so long as the output shaft/driveshaft yoke splines don't bottom out.

So to my thinking, you have no reason to adjust the axle-locating linkage. The "answer" is "zero half-turns".

You MIGHT have reason to shorten the driveshaft by the amount the transmission is moved rearward.

Am I wrong? Not understanding something everyone else "gets"?

[Dragncar]

Originally Posted by Schurkey

I guess I don't understand what's going on.

You're mounting the engine with a mid-plate. This pushes the transmission rearward by the thickness of that mid-plate.

The transmission has a slip-yoke at the rear for the driveshaft connection. The rearward transmission causes the splines to engage more deeply.

None of which changes the location of the axle. The axle doesn't move when the transmission is crammed rearward so long as the output shaft/driveshaft yoke splines don't bottom out.

So to my thinking, you have no reason to adjust the axle-locating linkage. The "answer" is "zero half-turns".

You MIGHT have reason to shorten the driveshaft by the amount the transmission is moved rearward.

Am I wrong? Not understanding something everyone else "gets"?

I guess I could have been more clear.
My drive line is almost too long. If it was a 1/2" shorter it would be nice. Its tight getting my U joint out of the yoke on the 9".
Nothing binds up, I have ran the axle all the way up and down as far as you can go (drive line hits the ladder bar cross member if you go too low) during mock up testing.
So there is not a lot of room to slip the trans yoke forward. .100 matters in my case. So I need my rear axle to be in the same place as before the mid plate.
And getting some more thread from my main rod ends will be a good thing.

The mid plate does not weigh much. .100 thick steel. Its a Alston unit and big enough for a chassis car. But by the time I am done cutting it up it will not be all that big.
Maybe I will put up a pic of what is left of it when I get that for into it. Right now I have several cardboard cutouts of my full mid plate.
There will be a lot of trim, fit, check, trimming of the cardboard before I actually cut the steel plate. I will need to have the trans and drive line all in the car with elephant ears in place before I weld anything.
And the headers will have to fit in there too. Thats why I might as well get my best set of headers have everything all dialed in and powder coat them inside and out.
Going to be a lot of work. Good thing metal fabricating is part of my job.