Head Swap

Ok im doing the head swap from a 90 gst to a 97 gsx and the guy that i doing the head said that it fits on there but there are some differences that will not let the head set right. So I was wondering if you knew what the differences are between the 2. And if it is safe to go on and do the swap but if not than i will just go with the orignal head. I really need to know the anwser to the question pretty quick so if someone could get back to me soon that would be great. The one thing that didnt match up was the spot for the thermostat so if i need to replace that won't be a problem he didn't put the cyclone on or the exhaust.
thanks everyone

i think you should do a search for 1g head or head swap. there is ALOT of information about that on here as well as all over the internet. its just to long to type out, sorry

I don't need details i just need general for putting.