Rollmaster Pontiac Red Series Pro Billet Timing Set, IWIS Pro Series Chain, .005" Short, ROL-CS7050-5

Rollmaster Red Series, sized .005" short for line-bored and line-honed blocks. Same K1045 billet steel sprockets and one-piece IWIS Pro Series chain as the standard CS7050.

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.

The chain is the difference. This set carries a genuine one-piece IWIS Pro Series full roller chain — 3/8" pitch, 1/4" British Standard double row — the same chain Rollmaster fits to its premium Gold Series sets. A one-piece roller resists stretch far better than a seamed chain, so your cam timing stays where you degreed it instead of walking retarded as the miles go on. If you have taken the time to degree a cam, this is the chain that protects that work.

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.