Need brake conversion help

[flyinlow]

I am helping a buddy convert front drums to disk. (72 Cutlass, sorry) I suggested a few choices, he went with the SSBC kit. It went on straight forwardly, bleed the brakes and new mastercylinder. Over two inches of freeplay and the braking was weak. Installed a new booster with different lenght push rods, none the right lenght, still the same. Put a pressure gauge in the front caliper. 1000 psi if you stand on them. Changed the M/C again with a Car Quest one that fit the push rod better...Good petal travel now, the braking is good on a normal stop , but weak on a high effort stop. You can not lock any tire no matter how hard you press on the petal. About 30 miles on the brakes now ,tried to do the moderate braking 50 down  to 20 braking to seat things (10 times). A little improvement, still weak on a hard stop. The car is still not ready for normal traffic. The brake lines are still using the stock distrobution block that the car came with. No perportioning valve came with the kit,I expected to be fighting with the rear brakes locking up too soon at this point , not weak brakes over all.  

Ideas?