I think they were different depending on the year.
Ive seen both colors used on GMC's.
The engine in my 45 is gray with a red cylinder head. It's a 248
I dont know if it is the original color. It has been rebuilt at one time.
The engine is not the original engine to the truck, but it is correct.
Last edited by JeffL; 07/02/2010 3:12 AM.