I.D. 340 parts

I looked up the casting numbers for the heads and the 3671587 is the correct head for a 73 340 and was also used on 73-74 and 76 360s.

The 3418915 would have been from a 71-72 340 engine or a 70-72 360 so it would be the one that's been replaced along the way.

I wonder if there's any difference beetween the two...I'll have to do some more digging.