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Old 10-28-2015, 08:43 PM   #95
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Join Date: Aug 2013
Location: aurora, il.
Posts: 1
Re: you want to change your 5X5 bolt pattern on 73-87 disc to 5X4.75

[QUOTE=502tripower;3031272]Now we all know that the 73-87 front crossmember and suspension components can be swapped into the 60-72 trucks. The 73-80 Chevrolet C10 pickups used a 1.28 rotor. Then in 81-86 GM switched to a 1" rotor. I did a bit more digging and found that the calipers are different for the 1" rotor but use a common bolt pattern with 73-80 so, it looks as if the 91 Camaro rotor will work on the 73-86 spindles if the 81-86 calipers are used as well. Also the flexible brake line will need to be changed if you have the 73-80 caliper as one of the calipers uses American standard thread and the other uses a metric thread. The parts house could not tell me which one used what thread but that they were different. I will figure that out when I purchase the parts. I have not done this yet but it does look like it will work. fones1966 a member here PMed me telling me about this possibility and I want to thank him for that. I just thought I would post this information in case there were others that could use it. Olympic Brake here in Washington is who provided this information. One note I want to point out is the specs that I have all show the same bearings on all three rotors. I was told by fones1966 that the 73-80 1.28 rotor used a A-5 inner bearing so that bearing would have to be replaced when switching to the Camaro rotor but, what I found was the 73-80 heavy duty 1.28 rotor used the A-5 inner bearing and the 81-87 light duty rotor used the A-6 as shown in the specs I have provided. I hope this information is helpful. Here are the specs on both the truck and Camaro rotors:

73-80 Truck rotor specs are:

Height 4.88
Diameter 11.85
Min. Thickness 1.220
Hub 3.06
Outer bearing A-3
Inner bearing A-5
Seal Part # 8871
Bolt Circle 5X5

81-86 Truck rotor specs are:

Height 4.63
Diameter 11.86
Min. Thickness .96
Hub 3.20
Outer bearing A-3
Inner bearing A-6
Seal Part # 8871
Bolt Circle 5X5

91 Camaro 1LE Performance Package rotor specs are:

Height 4.65
Diameter 11.85
Min. Thickness .97
Hub 2.78
Outer bearing A-3
Inner bearing A-6
Seal Part # 8871 ok....I know this post is old and I'm gonna ask for info outside of this forum but any possibility of swap knowledge or ideas could help....I want to convert my 1996 tahoe 2wd to 4.75 bolt pattern up front and run a 96 corvette IRS in rear....looked at camaro rotors no good and several more....any imput here would be welcome...Thanks, cliff

Last edited by vettemad; 10-28-2015 at 08:44 PM. Reason: im a dummy
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