70 mph is awful optimistic. I put big tires and a 3.5? rear end in my '54 and 55mph is really pushing things. Problem is the valves float.
If you are going down a steep hill and take you foot off the gas you will notice very little compression braking. Almost freewheeling. As you bleed off speed you will notice when the compression comes back. Valve float under load is a quick way to burn valves.
My owners manual (1954) states plainly:
"Sustained speeds greater then 45mph are not recommended".
Last edited by Tacoman; 04/10/2014 12:41 AM. Reason: clarify
