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Pushrods- Oil Restricted
Pontiac V8 Pushrods- Oil Restricted
Control the Oil to the Top End — Pushrods- Oil Restricted for Pontiac V8s
Oil restricted pushrods cut the amount of oil the top end of a Pontiac V8 sees. Every solid roller lifter requires oil restrictors in the block or restricted pushrods, and retro-fit hydraulic rollers carry their own restriction recommendations. Restricted rods do that job without machining the block.
Butler stocks Smith Brothers restricted chromemoly rods in 5/16" with .083" or .116" walls, 3/8" with a .145" wall, and 7/16" three-piece dual taper with a .165" wall, in .020", .030" and .040" restrictions, all built to your length.
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1. Why Restrict at All
This is a drainback and oil supply problem, not a horsepower one.
| Solid rollers | all solid roller lifters require oil restrictors in the block or restricted pushrods. A solid roller passes far more oil up the rod than the factory circuit was designed to return. |
| Retro-fit hydraulic rollers | Butler recommends a .020" or .040" restricted rod with the Johnson high performance and Comp Evolution lifters, and states that the short travel Johnson lifter must use a .020" or .030" rod. |
| Solid flat tappets | Comp's Pontiac solid flat tappet lifters are listed as requiring oil restriction along with longer pushrods. |
2. Picking the Restriction and the Rod
Two numbers to settle: the restriction size and the tube.
| 5/16" .083" wall, two-piece | available in .020" and .040" restriction, commonly stocked in .050" length increments from 8.500" to 9.350". Butler notes that the .040" two-piece is the same as the one-piece 581R and has no strength advantage over it; the reason to buy the two-piece is that it can be made in any custom length instead of being limited to .050" increments. |
| 5/16" .116" wall, two-piece | the heavier wall version, available in .020", .030" or .040" restriction, built to your length. |
| 3/8" .145" wall | heat treated 4135 chromoly, offered in .020", .030" or .040" restriction, for valvetrains that need more rod than a 5/16" can give. |
| 7/16" .165" wall three-piece dual taper | the biggest rod Butler stocks, a Butler Performance exclusive, offered in .020", .030" or .040". Note it cannot be used with guide plates. |
3. Orientation Matters
A restricted rod is directional. Installed backwards it does not do its job.
| Two-piece rods | the press-in side of the pushrod goes towards the lifter. |
| Three-piece dual taper rods | the restricted end goes towards the rocker arm. |
| Length is on you | every rod in this category is cut to a length you supply. Measure with an adjustable pushrod length checker with the lifter on the base circle before you order. |
Send us the lifter part number and the measured length and we will match the restriction size Butler recommends for that lifter.
Not sure what your Pontiac needs?
Call our tech team at 866-762-7527. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.