pierre-starlet

Hey people, I have recently put a 5k with a 3k-h in my 35 and has been going great untill. . . low compression in one cylinder then i replaced the headgasket. that worked fine untill a few days later and now it has happened again but in three cylinders, i have pulled the head loff and all looks fine so am thinking its a cracked head? :P I have a spare 5k head to put on but will this be fine to bolt on as it was a 3k-h head that was on there? Any help will be great, thanks in advance guys.