Posted by Kanavas on March 08, 19100 at 13:36:49:
In Reply to: Couple Flathead Spec Questions posted by GTK on March 08, 19100 at 12:03:30:
Max sustained speed for the engines is 2500. The difference from 2500 to 3000 is only about 5-6 mph. Why torture it?
The reason for the increased clearance is fairly simple.
As the trucks are essentially floored most of the time, they create more heat. A larger clearance allows a minimally longer closed time for the valves. This allows the valve seats to extract a bit more heat from the valve head.
sak