When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
i have have a 69 f-250 cs the c6 trans mission has been changed with one from a wrecking yard it has the internal linkage so i guessing about 70-maybe 75 how can i be sure?
I don't understand your question, or your referrence "internal linkage".
AFAIK a C6 is a C6. There is a difference in the shift arm on the side of the tranny. The truck runs parallel -- with the pan while a car points down / (not that far). There also can be tail shaft differences.
Check the rear Drivers side transmission casing for the casting number. This number can be decoded to find the original vehicle and year it was built for.