I need honest advice on what would be the best rear end to run in my Cutlass. I currently have a 7.5 with a Eaton style posi unit with 4.10 gears. That's all behind a built TH350 and 2,500 stall that's on a 450~500 hp Oldsmobile 350. I don't want to blow the rear sky high and at one point I was all sold on beefing up the rear end and not worrying but now with the power and that I want to take it to the strip a few times a year and then drive it home from there I'm concerned about the future of it. I really don't want to go with a 9 inch because I've already spent a lot on this car but at the same time I'm all for doing it right. With a 12 sec potential car, I'm just worried.
Forum advice for my car
- Thread starter Metzger82
- Start date
An honest 500hp Olds 350 is rare and expensive. Care to share the build specs and dyno sheets?
A 7.5 will hold up pretty well without blowing "sky high." If you can afford a 500hp Olds build, shelling out for a 9" shouldn't be an issue.
A 7.5 will hold up pretty well without blowing "sky high." If you can afford a 500hp Olds build, shelling out for a 9" shouldn't be an issue.
Fair enough, I like using figures of speech.
I can't say the exact power because I haven't dynoed the engine yet but the guy that helped me with the build and the specing of it, he swears by that number and obviously I can't say that it's what the engine makes but I would rather have something on the side of not worrying about it blowing in the future when I can't afford to fix it. And anyways when you built an engine after years of saving and now you're trying to save for the future I don't see why it hurts to save and look into other options.
I can't say the exact power because I haven't dynoed the engine yet but the guy that helped me with the build and the specing of it, he swears by that number and obviously I can't say that it's what the engine makes but I would rather have something on the side of not worrying about it blowing in the future when I can't afford to fix it. And anyways when you built an engine after years of saving and now you're trying to save for the future I don't see why it hurts to save and look into other options.
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FOR SALE - 8.5 G BODY REAR END
8.5 out of 84' Hurst Olds. Has 66K miles on it. Out of one of my cars. Lower control arm mounts cut off, was going to put the South Side Machine 4 hole lower mounts on it but never got to it.They are included with rear. 3.73 open. Not interested in shipping.Come pick it up in South Bend,IN 46614...
gbodyforum.com
Concur with Driven and Melloelky. Avoid sticky tires. Buicks require lots of work to rev durably. What's your driveshaft made of? The rear may not be the limiting factor until it's been abused.
What gearing is in you diff Metz? An Olds 350 is pretty torquey. The HP or the ET is not what loads or breaks rears. It's open differentials that are super hard on spider gears, drag strip launches with glue and slicks.
In my opinion the 8.5 is the perfect rear for an 11 or 12 sec G body. That price from the Hurst Olds will be sold before you can get there. It's price way below market value.
A S60 is way too much $$ for a 12 sec car and they are pretty heavy. Ford 9" are not efficient, which is not a deal breaker when a rear just has to be strong but it will slowdown a 12 sec car. Plus they are only good as a spool. The pocket bearing in a 9" forces you to run a tiny differential.
In my opinion the 8.5 is the perfect rear for an 11 or 12 sec G body. That price from the Hurst Olds will be sold before you can get there. It's price way below market value.
A S60 is way too much $$ for a 12 sec car and they are pretty heavy. Ford 9" are not efficient, which is not a deal breaker when a rear just has to be strong but it will slowdown a 12 sec car. Plus they are only good as a spool. The pocket bearing in a 9" forces you to run a tiny differential.
this aint exact video was lookin for but 7.5s might not be lost hope. chances are 28 splines were put in.
Yes the S60 is expensive and it is heavy compared to others. Depending on ratio, posi unit and brake setup it will get between 4-5k easily.
