i helped a buddie build one. we used the 4 barrel t.p.i. off a '90 some model van and piggybacked them together (i know this is not supposed to be done) comp cam for tpi 212 218 @ .050 .444 lift ported the stock heads 1 7/8 primary headers we ran 9.5-1 compression balanced the rotating assembly we also had the intake glass beaded. this all in a 86 2500 pickem up. 700R4 trannie which we redone with a trans pac and new servo's this thing will melt the tires off the rims ( we tried lol ) also has a 3500 rpm convertor. i don't know my chevies that well this was my buddies brainchild and just sits around collecting dust