JP Performance Pontiac Billet Double Roller Timing Set, 9 Keyway, .005" Short, JPP-5614LB-5

JP Performance billet set, sized .005" short for line-bored and line-honed blocks. Induction-hardened billet steel gears, 9-keyway index-marked crank sprocket, balanced cam sprocket.

Why a "short" set? Line boring moves the crank centerline closer to the cam, and a standard-length set goes slack. The correction is made in the sprockets — they are machined oversize to take the slack out. The chain itself is unchanged, because these chains are not produced in varying pitch lengths. Fit the oversize that matches how far your block was cut; if you are not sure, measure it or ask your machinist before ordering.

About the chain. This set uses a seamed roller chain — bushings are rolled and joined rather than solid one-piece construction, so it will stretch sooner under sustained load than a premium chain. For a street build or a moderate rebuild it does the job and saves you money. Running big spring pressure, a degreed race cam, or an engine you intend to button up and leave alone? Step up to the Rollmaster Red Series with the IWIS Pro Series chain.

The 9-keyway crank sprocket gives 8 degrees of advance or retard in 2-degree increments at the crank. The crank-to-cam relationship is 2:1, so that lands as 1-degree steps at the camshaft. Keyways are a solid fixture — they will not creep or walk the way an offset dowel can. Follow our Camshaft Degree Instructions and put the cam exactly where the card says.

Fitment — read this before you assemble. Pontiac crank gears were slip-fit from the factory, and aftermarket crank snouts vary. The billet crank sprocket in this set may need to be honed to the fit you want — some builders prefer a tight fit, some want a stock slip-fit. Check it on the bench, not in the block. More in our Pre-Assembly Tips.

Not sure which set your build wants? Our Cam Selection Guide walks through it, and you can always ask a Butler tech — we build these engines every day.