Engine - GM Performance Short Block Engines - Cast Iron Bow Tie Bare Block (3.98 inch Bore)

From GM Performance - Oil dipstick hole is not drilled and the lifter holes are finish bored to production diameter .842 inch. 2-bolt main bearing caps are installed to simplify the installation of the heavy-duty steel main caps with splayed outer bolts. Bow Tie blocks are designed for crankshafts with 2.45 inch diameter main bearing journals. The Bow Tie casting block P/N 10051184 is machined for a one-piece rear main bearing seal used on 1986 and later production small block Chevrolet V8s.