b17 and b16 heads are the same. compared to the gsr they also flow about the same too.....ive seen the flow charts n each has its advantages at certain points of lift. the gsr head will give a slight bump in comression due to the smaller combustion chambers.

it all depends on the deal ur gettin on the gsr head. keep in mind u wont b able to use ur b17 intake manifold. also, the gsr cams have slightly more duration than the b17s, (which wont make much of a difference bc theyre both stock cams). just things to keep in mind.

personally.....stick with what u have bc itl save u some money and its really not that much different then the gsr. ull get more compression but thats about it. g/l n keep us posted.