In the 1980s General Motors shifted away from small holes in the cylinder head and pushrod guide plates instead to what they refer to as “guided” rocker arms. These stamped rocker arms use two small ...

From trucks and RVs to boats, Chevy's 8.1L Vortec powered heavy-duty machines with massive torque. Here's what defined GM's final big block engine.

Chevy's Vortec 8100 — AKA the L18, AKA the Vortec 8.1 — was the last of The General's big block V8s, a line of engines that traced its lineage clear back to the fire-breathing muscle cars of the '60s ...