Large bolt pattern brake HELP! HELP! HELP!

Have you bled the entire system? Bench bleeding the new m/c is good, but you usually have to rebleed the entire system once the new m/c is in.

Sounds like you still have some air in the system if the pedal "pumps up". You shouldn't need a prop valve to get a stiff pedal, although you may need one to run the 11" drums in the back with the 10.87" brakes up front to get the front/rear braking bias right. And make sure your drums are adjusted properly as well like Redfish pointed out, if they aren't adjusted then you may be losing some pedal travel pushing the shoes out. 11" drums also have two different sizes for wheel cylinders, believe they're 15/16" or 7/8". You may need to change sizes to get things balanced out better.