I have a 77 460 that I pulled out of a F350 and installed it into my 77 Shortbox 4x4. In 1977 the engines only made like 215 or 230hp at the wheels was the rating. Torque is where it’s at. You can build a 460 with mild parts and they can make excellent horse power and you can easily start pulling upper 400’s to 500 ft lb of torque. This winter that is on my list. I picked up another complete 460 out of another 77. I’ll use that for the rebuild and I have a set of DOVE heads that will get ported for it. Then I can just do the engine swap over the winter. The one in my truck runs great and has 115k miles on it. I’ll drive it all summer as is while I get the other one rebuilt.

Sorry cannot answer the OP’s questing about the IMCO. I can look at my valve covers and see what it says on the sticker.

 

Don't worry about the OP. He was last here in August of 2005. This is an old, dead thread.