Coupe driveshaft alignment

[Cincy123]

Wanted to see if I could get some advice on my driveshaft for my Gen 3 Coupe (IRS, Coyote, T-56). The pinion angle seems good with the trans mount below the frame with the flange facing up. Looking at in from above and below, although not perfect, the side to side alignment is not bad. How close to "perfect" should this be? In order to it as close as possible to a straight line I can move the transmission on the mounting plate towards the passenger side, however, as you can see in the attached pics the bolts can't pass through the plate into the transmission mount without some modification. I am inclined to slightly enlarge the slots where the bolts pass through. The last two pics shows the driveshaft position without moving the transmission towards the passenger side. The first two show the transmission moved over with the subsequent lack of alignment of the bolt holes (that I started to enlarge with a file). Any thoughts or other suggestions are welcome!

[edwardb]

I don't know how much this helps, but this is how mine turned out with the same exact components. I didn't enlarge the slots. Not sure how much you're trying to get it "into alignment." Just like the side view has angles (e.g. pinion angle) the view from the top can too. Just so u-joint angles aren't exceeded.

https://hosting.photobucket.com/images/ab234/edwardb123/IMG_1213(1).jpg?width=960&height=720&fit=bounds (https://app.photobucket.com/u/edwardb123/a/1129060b-caed-4d4c-b98a-67a866e73c86/p/04880966-9504-478b-94bb-eb4c50456c4a)

[David Williamson]

Drive shaft alignment is getting the input and output parallel, some offset is good and required to make the "U" joints move to keep them lubricated.
David W

[Skuzzy]

Drive shaft alignment is getting the input and output parallel, some offset is good and required to make the "U" joints move to keep them lubricated.
David W

What he said. You do not want the driveshaft in a straight line between the transmission and rear end. You must have the transmission output shaft and rear end input parallel to each other. If you do not get that last bit right you will have problems.

[NAZ]

Agree with David and Skuzzy. On a street car, I target 1-deg of operating angle to keep from brinelling the u-joint bearings -- but that is not always practical. Parallelism of the trans output shaft and the pinion shaft under load is more important than operating angle (up to a point). Parallelism in both the horizontal and vertical. When you bump the tail of the trans to one side or the other while leaving the motor mounts in a fixed location -- what is that doing to parallelism?

This is why race car builders project a centerline down the middle of a chassis and place witness marks in strategic locations where they are easily picked up later. The engine, drivetrain, and suspension parts all get aligned off that datum which ensures the drivetrain is not skewed in the chassis.

Have fun with your build, I really like those cars.

[Cincy123]

Thanks everyone for the input. I will double check the alignment again and not shoot for perfection ;-)