So i played around with the online rpm calculator and with 3.23 Gear, 28" Tall tires, at 55 mph, with the 1:1 third gear of a TH350 i am looking at 2132 rpm. If i go to the 3.42 Gear i am only looking at 2257 rpm. Only a little over a hundred more RPMs so i am definitely going with the 3.42. Thanks for all the help and i will definitely let you know how the install goes. I hope to get it into the shop by the end of the week to get it done.
86 Cutlass Rearend
- Thread starter zildjian4life218
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You will actually see a little more rpm due to converter slip even if its just a factory converter.
I have thought it over so many times and i really can't decide between the 3.23 and the 3.42. The higher gear is gonna be more wear and tear on the engine, and of coarse worse fuel mileage. Will i notice a huge difference?
The quickest way to tell which gears you have would be to check out the trunk production code label. Most Cutlass Supremes from the 84-87 time period came with G72 2.14 or GM8 2.56:1 gears with the 307 "Y" motor and GU1 2.41:1 gears with the Buick 231 V6. GU4 3.08 and GU5 3.23 gears were available as options on 231 and 307 "Y" motors. 442's came with GT4 3.73:1. All of these were 7.5" rears expect the 442 which I believe was an 8.5".
http://www.vibratesoftware.com/html_hel ... _axles.htm
http://www.vibratesoftware.com/html_hel ... _axles.htm
wow ponchoman thanks for the link. That is a great site with great info. I do have the 2.41 gear set which will hopefully be swapped for a set of 3.23s soon.
okay so I just started my rear end gear swap, and i can't get the cross shaft pin out. I removed the bolt and the pin will slide back and forth about a quarter of an inch. Am i supposed to pound it out or is there some little trick that i might not know of. Thanks
It may need some persuasion but it will come out. Probably has a ridge in it from the spider gears. Sometimes Brake-kleen or carb cleaner will help if there is some buildup from cooked gear lube.
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