I have a 1972 Chevy Cheyenne pickup with a 400 engine.  It is all original and was never tampered with.  I can't find anywhere where this truck should have had this engine.  Can anyone help me figure this out? Thanks  

I have a 72 400 as well. It is a 396 that was made to have a bit more cubic inches. My truck has a 400 tranny as well. Mine is a Super Cheyenne with the camper option with the dual tanks and a blazer interior.  

I have a 70 chevy and I done some checking and they called the 396 a 400, most came out with the v8/400 on the fender. It is a 396 with about 400hp, that's what I was told from the dealer. If you want to check for sure you can run the engine # that is on the tab that sticks out just below the front of the head, I think is on the right side but it's been awhile since I ran my #.  

i have a 72 also that has 400 on the fender but the engine is actually a 402 big block that was made from a 396 being bored 30 over from the factory and when i ran the #s it is supposed to have 240 hp i just recently rebuilt it using a 284 dur.519 lift cam alum. intake and holley carb will post some pictures soon.  

Ive seen these before  -in Blazers also. but I don't recall the 402 big blocks having any badges advertising them as a 400.