BOP Pontiac Polymer/Composite Distributor Gear - .491 For Stock Type, TSP, RPC

SKU: BOP-PDG37

Pontiac polymer distributor gear, .491" shaft, for roller cams. Fits factory GM HEI, Pertronix HEI, points, Mallory (drill for larger pin), TSP RTR/Pro Billet, RPC S3922. MSD, Pertronix non-HEI, Holley and FAST need the .500" BOP-PDG38.

Pricing: $149.95

Description
Details
Shipping
Reviews

Description

Confirm your distributor shaft size — this gear is .491"

Shaft size is the #1 reason these gears come back. .491" and .500" look alike but are not interchangeable.
Use this .491" gear with: Factory GM HEI, Pertronix HEI, points, Mallory (Mallory must be drilled for the larger-diameter pin), TSP RTR, TSP Pro Billet, RPC S3922 / S3922BK.
Need the other size? MSD, Pertronix (non-HEI), Holley (including HyperSpark) and FAST distributors use the .500" BOP-PDG38.
Not sure? Check your shaft diameter to confirm size before ordering.
Ram Air V / 455 SD cam? Use BOP-PDG39 only.

Which Pontiac Gear Do I Need?

Gear	Use with
► BOP-PDG37 — .491" shaft	Factory GM HEI, Pertronix HEI, points, Mallory (Mallory must be drilled for the larger-diameter pin), TSP RTR, TSP Pro Billet, RPC S3922 / S3922BK
BOP-PDG38 — .500" shaft	MSD, Pertronix (non-HEI), Holley (including HyperSpark), FAST
BOP-PDG39 — .491" shaft	OEM-type 455 SD and Ram Air V cams ONLY (smaller cam gear sizing)

Roller Cams & Polymer Gears

Roller cam? You need this gear. Most distributors ship with steel gears, and a steel gear can damage a roller cam. Use a bronze or polymer gear with any hydraulic or solid roller cam.
Flat tappet cam? The polymer gear is a roller-cam requirement, not a flat-tappet one.
Why Butler uses polymer over bronze: in Butler's experience polymer gears last longer than bronze, and bronze debris in the oil can cause problems with hydraulic roller lifters of any brand. With polymer you never have to worry about metal shavings in your oil.
Roller lifters with good oil pressure put a little more load on the distributor gear — that's expected.

More: Pontiac Ignition Systems

Not sure which one you need? Ask a tech question or call 866-762-7527 before you order.

Butler Tech Library

Degreeing the Cam and Setting It Straight

A cam that isn't degreed in is a cam you're guessing at. Here's the cam selection guide plus step-by-step degreeing instructions.

Read the Cam Guide ›

Also HelpfulCamshaft Degree Instructions ›Cam Retainer Install ›