[Ron61]

Your motor should have double valve springs in it if it is stock. My 1969 Cobra with the 428 SCJ had them and I ran it hard and for over 10 years with no spring trouble. If it is stock then you should be able to contact Ford and find out what springs you need. I have since changed my cam and springs as I tried to keep up with the crap they call gas out here. But the stock setup would push the car to well over the 120 mark.

Ron