SBC BBC Thermostat Housing Stud Kit Bolts Stainless Kit Small Big Block Chevy - Bolt Kit for Installing Thermostat Housing to Intake Manifold - Fitment: Fits 265, 283, 302, 305, 327, 348, 350, 396, 400, 402, 409, 427, 454, 502 SB BB Chevy Engines; Fits Most Cast, Steel, & Aluminum Water Necks; May Not Fit: Water Necks with Recessed Bolt Bosses; Will Not Fit: GEN III, IV, V Engines (Vortec 4.8 5.3 5.7 6.0 6.2L, LSX, LT5 Engines). - Specifications: Hardened 304 Stainless Steel; (2) 3/8" x 1 1/2" Studs (polished); (1) 3/8" x 2 1/2" Stud (polished); (2) 3/8" Hex Locking Flange Nuts (polished).