I am going to go ahead and apologize as I know this has been discussed a lot but after a couple of days of searching I can’t seem to find anything with a more definitive guide with weight, converter and HP.

Bought a 65 Plymouth that I am going to try and race next season. I have a couple of options for an engine but was curious about what will live with the 8 3/4 (489). I am assuming I am going to weight in at 3700+. I can take the engine out of my Duster which is probably 530-550 hp- it goes 11.00 (1/4) at 3350 lbs, so I am guessing it will be an 11.50 car. The converter is about 5800. Would the 8 3/4 live ok in that environment?

Maybe. Especially if you put in a new ring and pinion every 150 runs.

I've known people who used them in lighter A-body and F-body cars that went pretty fast without hurting them for years. Excessive weight, stick shift, trans-brake, ect. is likely not good. Can always sell it before you break it, and use that money to go to something more durable.

Don't forget radials on a good track.

If you hook, hitting the 8 3/4 at 5,800 with 500+hp is going to hurt it sooner or later. I have always ran 8 3/4s and like them. But while it would otherwise live with that combo for a long time, it won't like that hit.

I run 3.91s in my 3,900lb Cuda behind the 540 HEMI. I can run it for years on the street with drag radials with no issues until I start hooking at the track and shocking it hard. Dead hooking will hurt it.

And don't forget to get good axles, too.

My buddies and myself have put hundreds if not 1000's mid/high 9 second passes at 3400 plus pounds and have broken exactly one 8 3/4 gear set and that one lasted 3 runs from installation, so it was improper set up.Other than that one, I've never seen one broke/break in our circles (stock caps and all)

So if your gears are properly installed they will last forever..

I think you're right about the point of maybe, maybe not, lol. It will probably live for a while.

Can an 8.75 work in that combo, sure.
But if it was my car, I'd put a Dana 60 under it and never have to think about it.
Which is what I did on my '64.
Maybe I'm too sympathetic about avoiding carnage and wall damage.

I've had the same 4.30 8 3/4 chunk in several cars. For years it's been in my 11.0@3385lb street car. Hundreds of passes on slicks. To be honest I've never broken an 8 3/4 R&P. Friends 65 Belvedere runs 11.4, Same 4.10 chunk for at least 15 years, It was used when I gave it to him.
Doug

Same here, 4.30 , 8 3/4,spool , 30x9 slick 3700lbs car 1.45 60' times, hundreds of passes. In 25 years only broke 1 R&P. 742 housing if that matters.

Also I should add the local people I'm aware of that had any issues with the 8-3/4 started to bend the axle housing tubes long before the case or gearset gave up. This was in drag race only use cars with slicks that were raced frequently.

Thanks for the reply, for those that responded that are running an 8 3/4, what are your or friends set-ups - axles, case, gear, pos or spool , backlash. I’ve read a few places were it seems there is a preference toward the 742 cases. I currently have a 489 with a 4.11. I haven’t taken it down yet to see axles or if the crush sleeve has been eliminated. I would be surprised if it had anything other than 30 spline axles.

I suppose I'm one of the unlucky ones. I had a 742, 4.30 in my 3350ish lb 69 Dart, it was fine behind the 340. It ran 11.60 with a 1.52 60'. It broke on the second pass that it hooked behind a 408 that I had built. The first pass it went 1.38 60'. It probably had 60 passes and a few hundred street miles, clutch type sure grip. The car was on 275 drag radials and the converter flashed 5400.

I rebuilt and sold the 8 3/4, then ordered a new Strange S-60. If I were doing it today i'd go with a 9".

I rebuilt and sold the 8 3/4, then ordered a new Strange S-60. If I were doing it today i'd go with a 9".

Curios why?

More brake and gear options, not to mention used third members and cases.

Interesting that they call the Dana 60 "relatively rare".

It's Motortrend so some of their info you have to take with a grain of salt. Passenger car Dana 60 axles may actually be somewhat more difficult to locate I would think? I've never tried looking for one, but I suspect you can't just find one in a pick your part junkyard anymore. I know junkyards here still have them in various older pickups so finding one of those is not too hard, but those don't just plug and play into an old car.

Neither do the phord rears. Unless it's another phord. And this web site is, by the way, about Mopars.

…..and you’re in the “race” section. We do what we want!