Ok, where can I buy a 17 tooth speedometer driven gear for 4-speed/TH350? TCI only goes down to 18-tooth ones.

The GM part number is 3987917, but I can't find it anywhere! I've checked NAPA, CarQuest, etc.

Anyone have a spare one taking up space in their shop? It will probably be purple.

National Parts Depot. PN# C-4337-7. $5.42ea.

I say go to a local chevy car dealer. Like a new car place, but it has to be one that has a parts dept. Call and ask to speak to the parts dept. tell them what you need. They will have to order it but they'll have it for you in a day or two

Got it. Thanks guys!!