Ordering a new rear end
 

I just ordered a new 9" rear end for my mini tubbed 69 Camaro. I thought it would be fairly simple, once I got the overall measurment, just call it in, answer a few questions, pay for it, then wait for delivery. A couple questions in, the guy stumped me, he asked if I wanted the drive centered, or the housing centered. I had no idea what to say. Is this a concern to have it one way or the other?

Thanks
Morley

We order our Mosers with the housing centered. Where are you ordering from. We have discounts on Moser.

housing centered.......much more appealing to the eye from the rear of the car

JMO, but ordering housing centered may look a little better but the drive shaft will not run down the center of the tunnel. The rear end yoke will be over an inch to the left of the tranny yoke. I don't understand why most people take the time to set the pinion angle and tranny/motor angle so the u joints are straight vertically and then order a housing centered rear. You negate all the previous effort. If none of thes items are addressed then no biggy I guess. Most cars sit so low these days, you can't hardly see the rear anyway. Just have to comprimise with form and function. Again JMO.

I've always ordered them with a centered pinion
$.02 worth

most cars we deal with we have to build the floor in so trans tunnel is no problem. It doesn't cause any driveshaft issues you can still set pinion angle....and thats why they are u-joints they dont care what angle or direction they are at. At least that is what I have always thought. If there is an issue with housing centered or how will it preform better I would be interested to know for future projects..........

I agree the tunnel is not a problem if you are custom building it, but retrofits in a stock floor pan could be an issue. As far as the u-joints, you are correct in that is what they are for, but you will have better longevity and less parasitic loss with as little misalignment as possible. I have no problem sacrificing some functionality for a look, but that is something you have to choose yourself. It's just that it is easier to make smart decisions when you have all the information. I guess that is my point here, I'm not saying one answer is right or wrong. I just wanted to present a few more things to think about before Morley makes a decision. Also, if side to side mis-alignment is not important then pinion angle would only be important for lubrication? Yes - No? it would be interesting to get some more thoughts on this. I'm curious.

Ordering a new rear end
 

Thanks to all who replied! This is a great site with a lot of knowledgable people. By the way, I went with the drive centered, found out the offset is only .9", don't think it will be noticable.


Morley

U-joints
 

Driveshafts have to have the same angle on both ends to eliminate vibration. When you move the pinion left or right you are inducing the same angle on the front and rear u-joints at the same time. The factory does this all the time for gas tank, exhaust, and suspention clearance. Take a look under 70s ford vans, the center section on the rear end is offset on one side by about 8 inches. The engine and trans are not offset.

If for some reason you can't create the same angle on both U-joints you need a double cardan joint (aka CV joint) on one end to eliminate vibration. Caddilacs and Ford Broncos use these from the factory on driveshafts. Broncos use them because the driveshaft is so short the angle is extreme. Caddilacs use them because the pinion is downhill to create tunnel clearance.

I centered the housing on the rear end I just built for looks and to move the driveshaft over so I could fit a torque arm next to it in the stock tunnel. Things that aren't symetrical drive me nuts.

This is good information. I didn't know the factories did it. When I was racing, we tried to keep the drive line as straight as possible due to parasitic losses. I had read several articles on this issue. One of the examples they gave was take a ratchet, 2 universals, and extension and a socket and put it all toegether with the ratchet as the tranny output and the socket as the pinion yoke. Then put it on a realatively tight bolt. Hold everything straight and perpendicular and loosen it. Then retighten it and loosen it again holding the ratchet offset to one side and parallel to the head of the bolt. It should feel just a bit harder to do. I tried it and have to say it is very subjective. It did however make sense to me with regard to friction and force vectors. However minute it may be it all adds up. Anyway great information as always.