Can anyone tell me the color of the wires and what post they go on the amp gauge. My 67 Barracuda convertible has 3 wires a black, red ,and red with a white stripe
The red/ white is an accessory and likely goes on the red wire. They should be marked and if not just reverse them if the ammeter reads backwards. Be CAREFUL Disconnect battery while screwing with them. They are NOT fused.
Replacement
Search in the for sale section here for 67 barracuda or 67 ralley.
For ebay etc prob best do it by the p/n which IIRC is printed on the gage face but may not be visible when installed.
IIRC 67 and 68 have the same face but 69 may be different. The speedo face is,
early 67 may have slightly different calibration - and to make this harder - new replacement oil pressure sending and fuel level sending units are not correctly calibrated.
Repair
Search for recommendations and experiences posted here.
There's a nice '67 120 mph speedometer with odometer for sale on ebay now. I almost bought it for the odometer parts, but thought it was too nice to part out. You can see it's missing the odometer reset shaft. I clicked it as "watch" and the seller sent me an offer. So he's a motivated seller.