Disc brakes locked

One quick question. Are you still using a drum brake proportioning valve?

You Have to swap out the valve when you change from drum to disk brakes!!!!

The drum brake valve holds pressure on the front brakes so that they start grabbing before the rear brakes. Other wise you end up with a ride that spins you out every time you hammer the brake pedal hard.

I had the exact same issue the O.P. is describing when I did my first drum to disk swap like thirty years ago.