CMS A-Series Race Camshaft – Leyland ST 649 Profile Equivalent
Precision In-House Engineering for the BMC A-Series Engine
Equip your competition engine with the legendary profile that has often been mimicked by competitors over the decades, yet remains the definitive, leading choice for serious race engine builders. The original Leyland Special Tuning 649 is arguably the most famous and successful full-race A-Series camshaft ever produced. Countless modern profiles have attempted to replicate its magic, but the classic 649 grind continues to dominate track days, sprints, and historic race grids for its unmatched top-end rush. Delivering a hard-pulling power band from 3,000 to 7,500+ RPM, it features a seriously lumpy competition idle and is engineered strictly for high-output motorsport use
Technical Specifications:
Application: Full Race / Track Day / Historic Competition
Power Band: 3000–7500+ RPM
Advertised Duration: Approx. 300° Inlet / 300° Exhaust
Valve Lift: 10.16mm Inlet / 10.21mm Exhaust (with standard rockers)
Full Lift: 102.5° ATDC (Inlet)
Valve Clearance (VC): 0.35mm (0.014") Inlet / 0.40mm (0.016") Exhaust
The CMS Core Exchange Service
This profile is precision-ground onto an original, inspected factory A-Series core. To purchase this camshaft, you can either:
First Option: Ship your original, clean A-Series camshaft to our workshop. Once it passes our strict structural integrity and gear wear inspection, we will dispatch your new CMS performance cam.
Second Option: Pay an upfront core surcharge at checkout. We will ship your CMS camshaft immediately, and refund the deposit in full once your usable exchange core arrives at our shop and passes inspection.
Installation & Break-In Requirements
To ensure the longevity of your flat-tappet A-Series valvetrain, CMS requires the following installation steps. Failure to follow these steps will void the product warranty:
Mandatory New Followers: Never install a new or reground camshaft with used lifters. You must use brand-new, high-quality flat-tappet followers. Check Valvetrain Geometry: Because this is a high-velocity regrind with a slightly reduced base circle, you must check rocker arm geometry. Ensure adjustment screws have proper thread engagement. Rocker pedestal shims may be required to restore a perfect 90-degree alignment. Break-In Procedure: Coat all lobes and follower faces heavily with high-zinc ZDDP assembly paste. Upon initial startup, do not idle the engine. Run the engine immediately at 2000 to 2500 RPM for 20 minutes to work-harden the new lobe surfaces.
Trademark Disclaimer
Classic Machine Shop CMS is an independent manufacturer of precision-ground engine components. Any reference to original manufacturer names, profile designations, or original part numbers is strictly for informational and comparative purposes to describe the physical geometric dimensions of the lobe profile. Classic Machine Shop has no official affiliation with these trademark holders.
