73 Dart How to identify a BB V8 K conversion?

Hello guys,
I bought 2 Darts a few weeks back. One is a 73 Dart Sport that has no engine. I am told that At some time in the 90s, the prior owner installed a 440. It has a spool type 73-76 V8 K member and the pedestal mounts are modified. There are 4 holes in the RH fender apron for spark plug access too. It has exhaust pipes that come up to what had to be exhaust manifolds. The car is an H code 340 model so I'd guess that I'd be better off with a 340 or a 360 in the car since my intention is to sell it. I'll probably pull the K member but I'd like to know what is the common modification that is done to these K members to allow a 383-400-440 to bolt in using the spool mounts. I recall reading about the DC K member that was offered by Dodge and Plymouth dealers and how enthusiasts used them as a pattern to modify old k members.
Any specific measurements would be helpful. Thanks, Greg