In the late 80's I pulled a stock 400 out of a 72 Caprice Estate wagon, replaced the rear main seal, stuck in an old 30/30 Isky solid lifter cam, an Offy 360 intake with a 650 Holley DP, a set of Hedman headers, a 454 flywheel, and had a shop in town build me a 3100# pressure plate and the best clutch disc they sold and stuffed in a 62 1/2 ton Chevy truck. It ran on 87 pump gas and it wasn't the baddest thing in town, but I did surprise a few folks. Don't try to reinvent the wheel.