1965 Dodge Dart stock differential advice

Stumpy said
Just throwing this out there.

After considering replacing the stock whiny 7.25 open diff in my mostly original 273 Power Pack, 4-speed 65 Dart with an 8.25, I decided that given how much I'd be spending to put in an 8.25 and things I have to change, I'd rather put a period correct diff in it. The car is a nice survivor and mostly stock and I'd like to keep it closer to original if I or someone ever wants to restore it.

I don't mind spending the money on a diff but am unsure which way to go. I wanted to go with an early a-body 8.75 from a similar year but they are practically unobtainium at any price. Open would be fine. Original 8.75 Housings are tough to find. Would a reproduction housing like from Moser be a possibility? I was also thinking that a 7.25 Sure Grip might be a better fit given the lighter unsprung weight and my driving style.

I've had many, many 7.25s. (at least 5) and not one has blown up on me. I'm well aware of the reputation of the 7.25 and the lack of availability of parts and gear ratios. I don't street race the car and I don't go to the track. I don't granny it, but I don't romp on it...well much... and I don't do many hard launches.

I could also find someone that will rebuild the rear AGAIN after only 3 years and take the time and care to work the whine out of it. Could I or should I just replace the open carrier with a 7.25 Sure Grip if I can find one? Parts again seem to be the problem. I'd like more cruising friendly gears than 3:55s and the shop that rebuilt my 7.25 last time said that was the highest gear available.

Thoughts? Pic of the car so you know what we are talking about.

View attachment 1716144108

I went through this same conundrum with my dart as well. Having a almost all original, begs the question, what do I do with it when the spiders in the 7-1/4 break... had originally thought a 7-1/4 suregrip carrier was my answer. Till it came to finding/affording one. Then finding parts to rebuild it if need be after that, is also a huge issue.

Though I've never seen full documentation that it was done to a 273-4bbl dart, supposedly you could order add-ons from the 65 performance catalog, which included an 8-3/4. I've heard of barracuda that have the option from 65. Don't see axle differences noted in the build docs that I have for the dart.

It's all besides the point. When it breaks, you have a broken rearend... no drive, no fun...

When mine broke, had already picked up a 8-3/4 housing and a few different pigs by then. 2.76, 2.93, 3.23 and 3.55 l for when it eventually happened. Sold the 4.10s and 3.91s that I had picked up a couple years before that.

The price of 8-3/4 housings has tripled since 2010, but can still find them for less that $1000. See one in for sale section with axles for less than $800 right now. Sure grip centers run a bit more than $500 used. New/rebuilt for much more.

If I had to make the switch over again, I'd do it with today's prices, and complain a bit, but figure the way forward to make it move again.

Just my $0.02. Hope it helps.