I don't know what parts store you work for, but this is what Autozone says about a 1986, f150 with a c6.

The VIN# is required to ensure that the correct part is shipped. Tag ID PGD-FG, PGD-FG1, PGD-GA, PGD-GA1, PGD-HD. "Please call for customer service and availability at 1-800-858-7269". "Expected delivery date does not account for the required special freight shipping. Most deliveries will arrive within 5-7 business days".

 

i called their customer service number and they where no help...........but they say the transmissions where the same size.

 

First, I know this isn't what you are looking for but have you checked out the cost to have yours rebuilt? I wouldn't worry one bit about a local shop messing it up. Most rebuild shops have been in business for years and can rebuild a c6 blindfolded. At least around here, these guys will bend over backwards to 'make it right' in case something does occur. In that situation just reasonably talk to them and don't do what is sadly all too common these days and post a rant on social media then expect them to help. I am having my C6 rebuilt soon and the cost is a few hundred less than the chain store unit referenced above. Again, this may vary by location but worth checking out.
​​​​

 

im looking into that now. its 1000 for a 3 year unlimited mileage warranty at work, if i can find a decent warranty im going to go ahead and have it rebuilt