Advise for rear end gear ratio
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Advise for rear end gear ratio
Hoping someone can help! I have a 92 Camaro I am changing the rear end. Currently car has a drum brake rear end. I have a disk brake rear end from an 85 trans am I’m wanting to put in it. Had a company go through the rear end to make sure it looks ok first. He is saying it’s a 3.27 ratio borg Warner from Australia. Should I keep that ratio in the rear end or is there another gear set I should be looking for while he has it there? I’m going to keep the car mostly stock just upgrade brakes and suspension. Thanks.
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From: 212 is up in this Bit@#
Car: Resto-Mod 1987 IROC-Z Clone
Engine: Alky fed L92 Vortec Twin-Turbo 6.8L
Transmission: My own built/ design 4L80M
Axle/Gears: Custom 12 bolt (4.10:1)
Re: Advise for rear end gear ratio
The only regularly available new Gear-Set for the Third-Gen Borg-Warner Differential is a 3.70:1 ratio Set.
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From: Meriden, CT 06451
Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: Advise for rear end gear ratio
Not knowing what a previous owner might have done, you need to measure the length of both of those rears - axle to axle.
The 92 rear should be shorter and require wheel spacers to keep the tires in the same location.
The 92 rear should be shorter and require wheel spacers to keep the tires in the same location.
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Re: Advise for rear end gear ratio
As said, 3.27 is an all-around "decent" ratio; not exactly "performance" oriented, but much more nearly so than some other options. Most likely it'll be fine for you, as far as just that one detail goes.
The one thing you're going to HAVE TO deal with though, is the brakes. That 85 rear will have the crappy Delco-Moraine system with cast-iron calipers, that are notoriously ... BAD in every way. Their hydraulic requirements are CONSIDERABLY different from drum brakes, meaning, your existing master cylinder and proportioning valve are not a good match for them. And then of course there's the matter of getting them to work at all, and then keeping them working long-term.
IMO there's more to be considered here than just the gear ratio. Personally, I wouldn't make that swap, but that's just me.
Overall length should be the same as what you have. 82-92 were all the same length, about 61½" between the wheel surfaces of the axle flanges. 93-up are longer, at about 64". The rotors or drums add another 3/8" or so overall to that.
The one thing you're going to HAVE TO deal with though, is the brakes. That 85 rear will have the crappy Delco-Moraine system with cast-iron calipers, that are notoriously ... BAD in every way. Their hydraulic requirements are CONSIDERABLY different from drum brakes, meaning, your existing master cylinder and proportioning valve are not a good match for them. And then of course there's the matter of getting them to work at all, and then keeping them working long-term.
IMO there's more to be considered here than just the gear ratio. Personally, I wouldn't make that swap, but that's just me.
Overall length should be the same as what you have. 82-92 were all the same length, about 61½" between the wheel surfaces of the axle flanges. 93-up are longer, at about 64". The rotors or drums add another 3/8" or so overall to that.
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Re: Advise for rear end gear ratio
As said, 3.27 is an all-around "decent" ratio; not exactly "performance" oriented, but much more nearly so than some other options. Most likely it'll be fine for you, as far as just that one detail goes.
The one thing you're going to HAVE TO deal with though, is the brakes. That 85 rear will have the crappy Delco-Moraine system with cast-iron calipers, that are notoriously ... BAD in every way. Their hydraulic requirements are CONSIDERABLY different from drum brakes, meaning, your existing master cylinder and proportioning valve are not a good match for them. And then of course there's the matter of getting them to work at all, and then keeping them working long-term.
IMO there's more to be considered here than just the gear ratio. Personally, I wouldn't make that swap, but that's just me.
Overall length should be the same as what you have. 82-92 were all the same length, about 61½" between the wheel surfaces of the axle flanges. 93-up are longer, at about 64". The rotors or drums add another 3/8" or so overall to that.
The one thing you're going to HAVE TO deal with though, is the brakes. That 85 rear will have the crappy Delco-Moraine system with cast-iron calipers, that are notoriously ... BAD in every way. Their hydraulic requirements are CONSIDERABLY different from drum brakes, meaning, your existing master cylinder and proportioning valve are not a good match for them. And then of course there's the matter of getting them to work at all, and then keeping them working long-term.
IMO there's more to be considered here than just the gear ratio. Personally, I wouldn't make that swap, but that's just me.
Overall length should be the same as what you have. 82-92 were all the same length, about 61½" between the wheel surfaces of the axle flanges. 93-up are longer, at about 64". The rotors or drums add another 3/8" or so overall to that.
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