This oil pump and screen are for use with the 454 cid (7.4-liter) HO (P/N 10185058) and 502 cid (8.2-liter) HO engine. These engines are Gen. V & Gen VI design with the one-piece rear main seals. This pump has a 1.3" long gear and will fit Mark IV engines. The distance from the mounting surface to the bottom of the screen is 5.87" and the screen is not welded. It is recommended that you tack weld the screen to the pump.