Finally Tested my 78 Mach 1

Hey guys, ive posted about my 78 mach 1 before. Well ive had it for probably a month now or so but still dont have it insured or anything so dont really get to drive it, but today when i got home and my dad was gone i decided i HAD to give it a test run ha ha. Well luckily i didnt get pulled over or anything but i took it down a strait away and you can guess what i was checking ! Well when when i tested it i was disapointed to see that it cuts out at about 85 MPH. Is there some kind of restrictor that i might have on this car that you guys know about? It was weird because it was in fourth gear (which is all it has) and i was cruising and at about 85 it just brings the RPM down to idle speed. Is there something mechanicaly wrong or is there a restrictor or something?
Thanks very much in advance,
Dave

Deffinetly hesitated a bit. Does that mean fuel starvation? Could certainly be running low on fuel considering the fuel guage doesnt work haha.
Thanks again.