Designed for 1961-1978 Chrysler 383-400-440 c.i.d. engines. These reconditioned heads come assembled with a "like new" appearance and quality with all new Aeromaxx parts nstalled and a milled deck surface. These heads have outstanding features that include premium one-piece, stainless steel, high flow 2.14 X 1.81 intake and exhaust valves. Heat treated, machined steel retainers and valve locks along with heavy duty valve springs are good for .509" lift cams. The 452/906 castings have a larger intake port volume than the standard castings for $599.00.