I need some input on a 1000hp 727 trans

the 76 is ok. you'll want to put in the pre 71 kickdown piston and springs. replace the planets with the 4 gear ones. replace the 3 clutch drums with the 4 ones and use a special cut pressure plate in the front drum to get an extra disc and steel in. replace any drum spacer that is plastic with the steel ones. use the wide end of the clutch clearances. use all the release springs in the front drum, 12 if i recall correctly. use any kickdown lever from 4.0-5.0. remove the governor weights.