When running a 383 or 400 S/B Chevy with a 153 tooth flexplate or flywheel, you need to have a balancing plate. These fit between the crankshaft and flexplate and correctly balance the engine without resorting to a big heavy flywheel.
Lets you balance your Small Block Chevy 400 or 383 with a 350 flywheel (manual transmission flywheel or automatic transmission flex plate) and a bolt-on balancing plate. Road and race tested. Allows use of lighter 350 flywheel to rev quicker. Precision stamped steel.
916-15375 Instructions (PDF)