Posted by Brian in Oregon on Friday, June 21, 2002 at 10:15PM :
In Reply to: top speed posted by pw stu on Friday, June 21, 2002 at 9:35PM :
Assuming you have 5.83 gears, 900x16 tire and of course your high gear is 1:1 on your tranny, then 45 mph is about 2650 rpm. This is considered the maximum sustained rpm for a stock 230 flathead. 55 mph would require 3200 rpm. You'd have to go to taller tires, or 4.89 gears, to achieve that with the 230. The drawback is the 230 lacks enough torque to make 55 mph possible with those changes on anything other than downhill or level ground with a good tailwind. A 251 PW has more potential. It can be worked over to raise the sustained RPM speed. Better still, it has the power to make larger tires or 4.89 gears a worthwhile option.