This is a good Engine Masters episode on carb sizing. The only problem with it is that you have to subscribe to get the ending. But there is still some good info in it.
www.youtube.com/watch?v=OMdsh9-PBRUDifferent size and different design carbs will display different strengths and weaknesses. One may drive better around town while another may put up better numbers at the track. 50 years ago, carbs were going to the spreadbore design and the center sections were going to materials that resisted heat transfer. Think Thermoquad. Today, those designs have even more positive effects that they did then.
I have said this numerous times in threads like this, the best street carbs out today are the Street Demons. They have features and benefits that the other, older design carbs do not. I have installed several and they are the best carbs I have ever installed on mild, primarily street cars (and trucks).
www.youtube.com/watch?v=IHWJpZCmUAk&t=31swww.youtube.com/watch?v=YNAlVFtUFL4www.youtube.com/watch?v=DPOuEOkazVc&t=308sThere are a tons more reviews on these carbs on Youtube. Either the 625CFM or the 750CFM would work on a mild 360. One might have advantages over the other that the OP would prefer. But the only real way to find out would be to test both on the vehicle. The primaries are the same on both size carbs. Only the secondaries are different between the 625 and the 750. So both would drive similarly around town and cruising. The difference would be at the secondary opening and at WOT. Does the engine need or even like the 125 extra CFM.
In considering these two carbs, if the OP wanted all he could possibly get from his engine, I would recommend the 750 knowing that it might require a bit more tuning. Maybe and then maybe not. If every last horse wasn't that important, then the 625 would almost guarantee a plug and play install.