SFI 153-Tooth Flexplate for TH350 Small Block Chevy

A 153-tooth SFI 29.1 certified flexplate for small block Chevy internal balance engines. PRW part number 1835002. It is chromoly steel, 0.035 inch thicker than a stock stamped plate, and the ring gear is double welded to the plate instead of spot welded, which is what keeps it together behind a high stall converter.

Fitment: Chevy small block 1957 through 1985 (and the 90 degree V6) with the two piece rear main seal and an internally balanced crank, so it runs no counterweight on the plate. The 153-tooth ring gear is the small diameter pattern, which is what you use behind a TH350, a Powerglide, or a 700R4 with the matching small starter nose. If your engine is a one piece rear main 1986 and later small block, or an externally balanced 400, this is the wrong plate - those need the weighted version.

Bench notes: check the ring gear teeth against the old plate before you bolt anything up. A 153-tooth plate in a 168-tooth bellhousing will not line up with the starter, and swapping tooth counts is the number one reason a fresh install grinds on start. Torque the crank bolts in a star pattern, run the converter bolts in by hand first so you do not pull the converter forward, and check converter to plate clearance before you snug anything down.

Why people replace one: cracked plates around the crank bolt circle and chewed ring gear teeth. A cracked flexplate makes a rattle or knock at idle that goes away under load, and a plate that finally lets go can take the starter and the converter cover with it. If you are pulling the transmission anyway for a rebuild or a stall converter swap, this is the time to put a thicker SFI plate in.