A few yrs ago I almost started one with my 400 block. A friend with a machine shop has done a few with cross bolted blocks & has a few cross bolted ones left. Stage 5 told me back then that the total cost for heads, valvetrain & intake was around $5700. I read an old Moparts post about one with a 400 block had pushrod/valvetrain problems but can't remember all the post said. I'd love to do one with a cross bolted 400 block.