So i have an antec 1200 case, and I know the 240 cooler should fit it in the rear, but I think I would like the extra cooling headroom of the 280. The 280 is actually 10 bucks cheaper than the 240 on newegg but not sure it will fit in my case without me having to modify it. I currently have a 120mm cooler master but I'd like to have at least a 240, as I believe this will keep my oc a bit cooler. 
 
If the screw holes are positioned in the same spot on either one I could would probably have room but looking at the specifications I would think the 140mm fans have the holes further out than the 120mm fans.
 
Also should I even bother to upgrade as when I oc 200 mhz I'll hit around 72°c. Anyways, if I do decide to upgrade I would like to save the 10 bucks but that's not a deal breaker as I'd rather not have to modify my case. Thanks for reading and happy new year's.