ARP Rod Bolts

ARP’s rod bolts are sold in two ways: complete kits for a named engine’s connecting rods, and replacement bolts for aftermarket rods, often supplied in pairs. The kit title gives the engine family and, where it matters, the thread, from metric M8, M9 and M10 to 5/16, 3/8 and 7/16 inch.

The material steps up with the build. 8740 chrome moly is the standard grade, ARP2000 is the common upgrade, and Custom Age 625+ is the top grade listed here, with a few kits in L19 or MP35N. Wave-Loc bolts appear in many kits for older V8 engines, and some kits are press-fit designs.

Most kits are chosen by engine, not by car; a few are also listed for BMW, Honda, Peugeot and Toyota models in the fitment data.

Rod bolts are tightened by stretch as well as by torque, so follow the figures and the lubricant in the kit’s instructions, and measure stretch where you can. Fitting new bolts changes the clamping of the rod cap, so have the big-end bores checked for size and roundness before the engine is assembled.