Yes, smaller. IIRC (and to say for 100% sure) that the 1/2 stud uses a 3/4 6 point nut and takes a 3/4 socket (that I'm sure of) and the 6 point uses a 1/2 socket (I'm pretty sure on that...that is the biggest it would be) so it's a pretty big reduction in diameter.
There are some heads that you have to mount on the block and remover the 3-4-5-6 exhaust springs to get them together. When everything is torqued, you put the springs back on. PITA but if you want to make HP it is what it is.
