I have a 3.73 disc rear from an 84 TA, which I am swapping into an 87 Firebird. I know the early brakes aren't as good, but the calipers are being rebuilt with the "recall kit" so they should be fine for now.

The 87 has the J50 master cylinder and stock drum brake valve. I have the 84 disc valve (which is standard thread and won't work with the existing MC right?) and a stock 91 master cylinder and drum brake prop valve. I plan to use the stock 87 master cylinder (its in great shape, and its polished!), but wanted to know what prop valve I should use. Can the 91 drum valve be modified, or should I buy a new prop valve? I saw the 1LE valve suggested on another thread, part # 14089496, but wonder if this will work ok considering the car has stock iron calipers in the front and the early iron calipers in the rear.

Any ideas? TomP?