I have a GV unit in a 65 coronet, and the speedometer is WAAAAAAAAAAAAAAAAYYYYYYYYYYYYYYYYYY off.
Does anyone know where to get the correct speedometer gear from? I have tried to contact GV several times about this, left a message, emailed a few times but have not heard anything back. I understand they may not be in office, but I sure would like to know where to get a gear for this.

Is it a standard cheby thing?

The speedo pinion and adapter are standard TH400 parts. In fact, GV has taken over production of the parts since the GM bailout.

Lots of adapters and pinions on E-bay.

fantastic, thank you guys

You might want to figure out how far off it is, by comparing miles on the odometer with miles on a marked highway, or using GPS. Keep in mind that the speedometer might be out of whack, so even if it's being driven by the correct gears to give 1000 turns/mile, and the odometer reads right, the speedometer does not show the correct speed. I like to make sure the odometer reads right, then adjust/repair the speedometer as needed so it reads right, also.

They used a couple different sizes of speedometer gears in TH400s, base on tooth count..mostly the gears with 30something teeth are a little smaller diameter than those with 40something teet, and there is a different speedometer sleeve (housing) used with the different size gears. Not like mopars, that have the same housing and just install it in different positions for different tooth counts.

if you need more info, ask away...speedometer gears are one of my hobbies, since I have to deal with them so often