I'm thinking about swapping a 4th Gen Rear into my 91 RS 305. My question is if i get a 4th gen with disc breaks on it, do i need to change the brake booster or any of that brake stuff?

 

its a 100% bolt in, put a master and prop from a 3rd gen with rear discs

your wheels will look stupid, need to get wheels with a 4th gen offset and spacers for the front

 

I'm already running my car with C5 Rims with 2" adapters all around... I'm looking to swap the rear 1. cause my rear is blasted and 2. to get rid of the adapters in the rear.

So all i need to do is get a master and prop from a 3rd gen which had disc breaks and swap that in?

 

yes it will all bolt right in. you might want to use a 4th gen or aftermarket torque arm b/c they are a lot sturdier than the stock 3rd gen ones.

you don't really even need the master, just the prop valve. i went from 3.08 single track w/ drums to 3.23 posi w/ disc brakes and it was amazing how much nicer it felt. You don't realize how bad the brakes on the 3rd gens are until you upgrade them.

you will be happy w/ the swap, at least i was.

 

residual check valve is in the master on drums

 

What size are your rear C5 wheels? If they are OEM 18x9.5 from a vette, you may need a 5/16" spacer with the 4th gen rear to keep the lower inner portion of the tire from hitting the frame/inner fender well area, near the LCA on the body.

I am still using the stock drum prop valve, works fine, but I may just change the prop in the future just to make it all correct.

 

The fronts are 17x9 and the rear are 18x10

 

Does anyone remember what the ebrake cable part number is for this retro fit ?