GM Gear Reduction Starter Upgrade

PMGR is short for Permanent Magnet Gear Reduction. What exactly does that have to do with an upgrade? Well, it means that when retrofitting the older positive engagement starters it provides a 50% weight reduction (8 vs. 20) and requires less cranking amps. And because the PMGR starter is a smaller size, it provides better header clearance and reduces the effects of a hot start and your vehicle will be easier to jump start too. The only down side is that these starters do cost more than the old style starters.

Basic flywheels/flexplates and starters in the GM realm.

GM, for the most part, uses two different sized flywheels and or flexplates on most of the GM small-block V8, big-block V8, and V6/90° engines. The difference is that flywheels are used on manual transmissions and flexplates are used on automatic transmissions. Because of these diameter and tooth count differences there are two families of options.

Large flywheels/flexplates are 14" in diameter, have 168 teeth and have two offset or staggered bolt holes

Small diameter flywheels/flexplates are 12-3/4" in diameter, have 153 teeth and have two bolt holes which are parallel.

Note - Many GM blocks come with both patterns drilled. If you are mixing or matching your engine/trans combination you can get the correct starter to fit the new flywheel/flexplate by installing the starter that matches your new combo.

GM V8 Applications (Small Block)

168 tooth flywheel up to 96 (except 5.3 / 6.0 engines) use Lester #6449

153 tooth flywheel up to 96 (except 5.3/6.0 engines) use Lester #6470

All Chevy/GMC with 6.0 engine 98-05 use Lester #6492

All Chevy/GMC with 5.3 engine 99-06 use Lester #6494