72 Challenger with a 400. That is a dirt track car and we were able to use a big block because the rules said engine could be year make and model. The 400 was a replacement for the 383. Has lower compresson, but bigger bore. Otherwise same motor same heads, crank, rods, cam and intake. It is a "B" engine. The 361, 413 and 440 were "RB" and used longer pushrods and wider intake among other things. They used the same head. The 413 had closed chamber heads but smaller valves use mostly in trucks. We used the 413 heads, but we hogged out the valves to use the bigger ones from the 440. Milled the deck .015" we were close to 14 to 1. Used the supersunco racing gas. The Challenger was a unibody car and that is not ideal for a dirt track so we took the front clip from a 71 fury with the tortion bars and transplanted it to the Challenger. used 2x6 steel to tie the rear and the front and added the full roll cage. The car was a powerhouse and very fast. With that front clip was a bit darty. Looking back would have made a better drag car, but we had some wins and a whole lot of fun. That photo was from 1993.