Some of you may know this already, but I've never seen it written down anywhere. I sure hope it helps someone, it would have saved me a lot of time.
I've had 3 Challengers with 7 1/4 rearends and although there is nothing wrong with them, they are light and pretty tough and do just fine behind anything that came from the factory with a two barrel carb. The one in my current car even has 3.55 gears and has held up fine behind a hot 318. But if you start adding more power, you really want to step up to an 8 3/4, or a Dana 60 before it explodes at a stoplight while the rustang in the next lane pulls away laughing.
With the first two Challengers, I had no problem finding an 8 3/4 from an E body, they were as close as the nearest junkyard. Of course my last Challenger project was 10 years ago and finding an Ebody, let alone one with an 8 3/4 in a yard these days is pretty much impossible. So for this new project, I needed to find an economical alternative for my old 7 1/4. I could have one cut down like the A body guys, but thats pretty pricey.
So I started searching online for options and came across a reference table showing Mopar rearend dimensions. I'd seen these before, and there was nothing close to an E body, but there were models on this list that I hadn't seen before. Then there it was, a lowly C body, and even lowlyer (is that a word?) A100 Van listed with nearly the identical dimensions of the E body.
I didn't think it could be possible, but I thought I'd check it out. Being in a very rich old junkyard area of Central Texas, I went out to my favorite yard and started measuring. After a couple of C bodies I was about to give up, but then I measured a new addition to the yard, a 66 Newport, and measured it again.....and sure enough it was spot on to the dimensions given in the table shown below. I couldn't believe it.
Differences in 8 3/4 Rearend Sizes (inches)
'65-'69 C-body and A100 Vans E-body Difference
Housing Widths Flange to Flange 56.75 56.48 0.27
Axle shaft length 30.00 29.97 0.03
Rear end Widths Drum to Drum 61.75 61.63 0.13
Perch Widths Center to Center 46.00 46.00 0.0
"How much for the rearend" I asked. "Which one?" "That C-body over there" I answered, nervously awaiting his response... "Don't get much call for those...A hundred bucks?" I said "sounds good" but inside I was like "Score!" He put the car on a rack and I pulled the complete rear and U-bolts and it even had brand new 11x2.5" drum brakes and new right-hand lugs on it.......Sweet!
So, there ya are, go get yours before they are all crushed. Make sure you check the year and measure first as some 65-69's didn't have those same dimensions. A quick spring to spring centerline measure should do it, 46" and you found a winner.
