Here is a 550hp/500ftlb 6 liter LS pump gas motor being set up ready to turn a Southern Jet 8 1/2 two stage.
These motors have the under driven balancer and we under drive the alternator and add pulleys as these things spin up like you wouldn't believe!!
We also make a billet 6061 flywheel with rear hi torque starter (pics of it being machined)