273 Engine _ Need ID of Intake

65Val said

...

I believe that the 4294 carb only has the NARROW, square bore bolt pattern carb flange. You can drill the carb base for the WIDER pattern that will fit your 340 intake, then you won't need any adapters...or, get a newer carb with the WIDE pattern already there (Edelbrock Performer or Carter Competition AFB )

Click to expand...

This is what I was trying to say above. Although I hesitate to suggest it also. First because I hate to see the original carbs modified. The second problem with the 4294 on the 340 intake, is using the factory choke. The 340 choke won't work with the 4294 and the 4294 choke is in a different place on the 340 manifold. If you do get a 273 4 barrel manifold you need a 66 or 67, since the 64 and 65 have smaller intake bolts at a different angle.