Hey y’all! I just had a 1999 GMC 1 ton single cab, with a 545 gasser, and a 4L80 transmission given to me. I shortly found out that the motor was locked up from rust, from inspection I think the head gasket is bad. However I was wondering what Diesel motor would be the best to swap with the 545, How hard it will be, and the steps I’ll need to take? Any suggestions?