ok i have a 87 cutlass 442 that has the 8.5 3.73 my buddys has a 85 grand pirx and its a 7.5 but what is the gear any one know he wants to trade me and give me $700 also i am running a th400 and as of right now its hard to ride on the freeway to hight of a rpm so what i want to know if i swapp rear end will it help me with the rpm on the freeway
?s stock gp 7.5 rear end vs 442 8.5
- Thread starter scooba1324
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Answer number one DONT TRADE HIM! Those rears are known to be weak
and if you beat on it alot and plan upgrades, Engine,trans,sticky tires. It will not live long. Spend the three hundred bucks or so and change the rear gear and keep what you have!
and if you beat on it alot and plan upgrades, Engine,trans,sticky tires. It will not live long. Spend the three hundred bucks or so and change the rear gear and keep what you have!
KEEP THE 8.5" REAR!!! They are highly desirable, some people would sell a kidney for one!
Seriously, like the previous poster said, change the gears if you want lower (high numerically) gears. I'll cost you a couple hundred bucks.
You'll regret going with the much weaker 7.5" rear. It won't last too long, especially when you get good traction . . .
If you want better economy swap to a TH200-4R overdrive transmission and keep your 3.73's (or go with the GN gears, I forget what they had--3.5? something?).
The 3.73 gears gave that 307 all of its balls, IMO. change to something a lot lower and your car will be a dog off the line.
Seriously, like the previous poster said, change the gears if you want lower (high numerically) gears. I'll cost you a couple hundred bucks.
You'll regret going with the much weaker 7.5" rear. It won't last too long, especially when you get good traction . . .
If you want better economy swap to a TH200-4R overdrive transmission and keep your 3.73's (or go with the GN gears, I forget what they had--3.5? something?).
The 3.73 gears gave that 307 all of its balls, IMO. change to something a lot lower and your car will be a dog off the line.
no 307 any more and all i here is bad stuff about 200r4 i had 2 of them and they both would slip when i put my foot in it but it was great for just crusin so i should find another 200r4 or should i get my old one rebuilt
Well, there were different versions of the TH200-4R. for example, the Grand Nationals and 442's, Hurst/Olds had strongest ones with different shift points calibrated for performance. I think the Monte SS's had the next strongest, and then the other cars usually had fair TH200-4R's that usually don't hold up to well to a lot of added torque.
I'm sure other posters will chime in, but your best bet is to keep that desirable 8.5" rear--and if your looking to get your RPM's down and don't want to swap in an overdrive transmission (200-4R or 700-R4), i'd would just change the gears to something like 3.23's.
I'm sure other posters will chime in, but your best bet is to keep that desirable 8.5" rear--and if your looking to get your RPM's down and don't want to swap in an overdrive transmission (200-4R or 700-R4), i'd would just change the gears to something like 3.23's.
The issue may be the TH 200 4R you were running. Stock, they are not very strong, especially the versions in the non performance applications. However, you can have it built to take impressive power levels if you are willing to put the money into it. If it is a street car, this is the route I would take (short of a manual conversion). I would NOT trade an 8.5 for a 7.5!!! The only reason to trade for another rear is if it is a bolt in 9 inch, 12 bolt or Dana 60 with stronger than stock internals.
if you take the 8.5 out of the 442 and put in the 7.5 it would be similar to putting a 4 banger into a 68 camaro ss, does that put it into perspective? it will take away allot of value in resale also if you ever sell it. i would say you are a crazy fool to agree to that one but thats my opinion
I would like to add something here. Now I agree with everyone else not to make the deal, that 8.5 is what you want. But at the same time, whoever made you the offer is not ripping you off. It would be a good deal for you (in dollars), but a bad deal for your car lol.
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