[bruceman1968]

Just did some more research, 3999290 could be 68-72 402/396, so we need the date code to see if you have the 71, 402 310hp or the 72 402 210hp.
The 71 motor could have a auto or manual trans. The 72 motor was a auto. I'm betting on the 71 as the 72 was a prob. a car motor, although some references list it as a truck motor.
Check the date code for a definitive answer. I'm betting the date code starts with a K and ends with a 1. Should be 2 numbers in-between.