I'm not gonna lie...I'm not to savvy on rear end swapping. (but Im learning) I'm not even sure how to phrase things correctly in the google machine for results so I gotta open the door here and ask... When swapping rear ends that are the same overall width but pinion center line may be different between the two by a 1/2" or so, will the u-joint compensate for that? I was planning on putting a 1st gen Camaro rear under my 49 Merc. My research told me that 68-79 Nova rears were the same as the 1st gen. I bought what I thought was a 70 Nova rear but turned out to be a later model 7.5" Nova from probably 75'. Its the same overall width, but I think the pinion centerline may be different than the factory Merc- hence the question. Thanks guys.
you should be fine. plenty of guys put off center pinions in cars. in fact my avatar has one off by a couple of inches and it runs fine. if it starts getting crazy off then you would need to center it and change the track width with some offset wheels.
If you can obtain an angle gauge, set each end; pinion, and tranny tailshaft, so that these parallel 'shafts' are offset to have a three degree angle w/the driveshaft. Five degrees is okay, (adjust the pinion and tailshaft until you have equal angles). Limited motion in a u-joint helps ensure grease to the rollers.
Considering that virtually ALL the cars that were equipped with offset pinions from the factory ran just fine, it puzzles me why this question keeps coming up. The u-joint really doesn't much care how it is 'clocked', so long as the resulting angle does not exceed it's operating range. For normal street driven vehicles, this just isn't a problem. Ray
It won't be an issue as far as U joint wear. On the Merc it might be a bit of an issue if the car is lowered a bit because the driveshaft tunnel is pretty narrow. I had a 65 Chevelle rear in my 51 for probably 50 thousand miles and never had a U joint problem but the driveshaft rubbed the tunnel when I had any load in the car.
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