SPOOL 8HP45/8HP50/8HP51 or 8HP70/8HP75/8HP76 Billet Main Shaft

SPOOL 8HP45 / 8HP50 / 8HP51 & 8HP70 / 8HP75 / 8HP76 Billet Main Shaft

We spent 3 years developing this shaft to build something we genuinely felt was missing from the 8HP market — a true billet main shaft made for serious power.

This shaft is CNC machined from billet 300M steel, giving us the strength and consistency we were looking for from the start. We put a huge amount of attention into the machining and quality control, especially where it matters most.

The splines are machined to extremely tight tolerances and are checked carefully to make sure everything fits and engages properly. The shaft is also nitrided for surface hardening, giving it a hard, wear-resistant surface while maintaining the strength of the 300M material underneath.

This wasn't an overnight project. We spent three years testing, refining, machining, and going back to the drawing board to get it right.

• Free US shipping on orders over $250.
• Free pickup at our Dallas shop, usually ready within 24 hours.
• Unused parts can be returned within 30 days. Tunes, opened electronics, merch and installed parts are final sale.
• Want it installed? Book the install at thegbmotors.com.

Full details are on our shipping and returns page.