Put Wilwoods on all four corners, now the brakes stick....What the heck can cause it....I am thinking the master cylinder had the seal baked out of it due to fender well headers, but with only a week and a half to go, I need consultation....

Did you check the length of the pushrod to make sure it isn't too long? That is my first guess.

Open a bleeder and see if it corrects it.. did you
center the caliper to the rotor

Calipers were all shimmed to center..and the brake pedal can still be pulled back further...This was a working setup when it had drums, so I am a little confused by this issue. If I tinker with the pedal, they all free up.

did you remove all the old plumbing the prop valve etc? you need to get rid of all that and run a new style 15/16 master cyl

take the plunger off and see if that releases it?

one other thing to check is the black flex line on the rear especially if it is stock, they will fail inside not letting pressure release

Loosen the master a few threads and see if it still
does it

Dragula when I put Wilwoods on my Cuda in the late 80's I had the same problem. If you are using the stock MC there is a small pressure valve(that keeps a small amount of pressure on at all times for the drum brakes) that can be removed from the MC. I used a small screw put it into the seat(where the line for the rear brakes entered to MC)and wiggled the seat out. I removed the valve and bingo no more drag. I've had this set up since 1988. If you have an aftermarket MC not sure if this will help. Wasn't sure which MC you were using.

nothing left but the master cyl, take the lines off and see if it releases.

All drum brake master cylinders have residual valves, usually around 10 lbs, in them somewhere, usually behind the brass seats that the brake lines hold in As already mentioned check that now by removing them with a # 8 sheet metal screw turn in 2 or 3 turns and then pry the seat out, the valves are rubber flapper valves with a small stainless spring inside the valves Remove them and throw them away and resaasembe the seats , make sure and crank down on the brake lines but don't strip the threads out of the master cylinders Same thing on the new matser cylinder also. On cars that have the master cylinders lower than the brake calipers you will need a 3 lb residual valves (Wilwood sells them )so the brake fluid won't drain back and overfill the master cylinders and leave air in the brake calipers

It was an after market master cylinder....Just got the new one todayoks identical...

Strange = Mopar.

What if there was old DOT fluid still in one of the lines when I put in the Wilwood fluid?

Well....How about reversed lines off the Master Cylinder!!!!!

Bingo!!!!!