TIME-SERT GM Cadillac Northstar 4.0/4.6 V8 Part # J-42385-500 NorthStar M11x 1.5 Headbolt V8 This block has 1 depth for all head bolt holes. Last year for this block 1999 TIME-SERT GM Cadillac Northstar 4.0/4.6 V8 Part # J-42385-500