Which 360

I agree with Rob. Get the roller if you can. I'm pretty sure all 89's are rollers. I know a 89 318 a buddy has is a roller. If you don't get the roller the 74 would be 2nd best unless it has a bazillion miles on it and the 84 is low mileage. Some guys say their thicker castings. I don't know if that's true or not but they were made out of better material before 76 so they usually wear less.

Depends on how much hp you want to make as to what heads to go with. The 89 should have 308's on it. I've heard their good swirl port heads but I've never seen any so I can't verify that. Magnum heads are good performers but watch about used ones because they had a problem cracking between the valve seats. Then you have older J or X heads which are good performers and have the potential to flow enough to make 525-550 hp but that takes some work. If your wanting to go that high you might as well buy a new set of Eddies.

BTW: I just realized you said the 74 was out of a New Yorker? I'm nearly positive New Yorkers and Newport's only used big blocks. My grandpa had a 74 New Yorker and it had a 440. The 360 was usually only found in lower line of C bodies and trucks. You might want to check things out closer when you buy it to make sure their selling you a 360 and not a 318 cause it sounds like they have things screwed up.