My 86 came with 4 wheel disc from the factory and I'm going to be isntalling the LS1 front brakes with the 4th gen rear. Is it necessary to do the 4th gen booster assembly as well? I have read the 4th gen bore size is bigger to support the larger brakes but I am not sure it is needed since my car already has 4 wheel disc. I have C5 replica wheels so the I doubt the fitment will be an issue.

 

No need to swap in the LS1 M/C. the stock set up will work.

I would recommend that the stock combo valve be either done away with or properly gutted. Then an adjustable proportioning valve be placed in the line to the rear brakes. This will give the best performance from the brake upgrade.

RBob.

 

I've upgraded to the LS1 front and 1LE rears. I'm using a master/prop valve from a 4 wheel disc 86 Camaro and find the rear braking action to be lacking.
It was suggested that a prop valve from a 90-92 may solve the issue as the bias is different from that of the earlier years (credit to JamesC). I've yet to try it out. Failing that (I'm trying to find one at the moment) I may take RBob's advice and try an adjustable unit.

 

I'm not a fan of the adjustable valves even though I have one on my 81 camaro and haven't had any issues. I guess I'll try and gut the existing prop valve and see what that does for me. Also, I may have a chance to get a set of STS-V front brakes and I want to know if they are the same as the CTS-V. I know the STS has a 6 lug rotor but can I just swap that for the CTS version? I know I will need the LS brake brackets before I do this but if I can get the STS-V setup, that will be sooo much better.