Yes the 340 driver is actually 2 1/4". The 60s 340 passenger is 2 1/4". The Jeep magnum is 2 1/8". The 70s 340 passenger is 1 7/8". The 273/318 are 1 5/8"....I've never had a 273 manifold so it could be smaller than 1 5/8"????.
The ones I found are casting number 3614395 (71-73 340).
I've seen those listed as both 72-73 318's and later 71-73 340's parts . Can anyone confirm or deny? If they are correct on a 340, then they should be 1-7/8?