Just picked up a 1979. Previous owner apparently put a 289 in it with an auto C4. The transmission has some issues when you go into Drive as it takes a little while for 1st hear to engage. I'm thinking it's the torque converter but not sure. I figured these transmissions would be everywhere due to the amount of vehicles, they came in. But having trouble locating a replacement locally. Was unsure if I should go with a C6 instead but didn't know how direct the swap is. I have limited mechanic knowledge and even less limited free time, so most likely will be paying to have the work done. What do you guys think?

Secondly, I am trying to work out what all was ruined on the dashboard as there are a few things that look out of place. The truck came with AC but I think whoever replaced the motor didn't have the necessary brackets to mount the AC so now the compressor and other integral parts are missing. Does anyone have a picture of a factory dash from 1979? Thanks for the advice!

 

A C6 may or may not bolt up. It depends on whether you have an early or late 289 and what the C6 is out of, see this list of bellhousing patterns:

https://en.wikipedia.org/wiki/List_o...using_patterns

I think 2wd and 4wd transmissions are different, the tailshaft bolts to a transfer case if it's 4wd. You also may need a different length driveshaft.