Posted by Ed Kammerer on October 28, 1997 at 10:43:48:
In Reply to: RPM's at cruise posted by Gerry Zell on October 27, 1997 at 17:55:59:
:
: About the M-37:
: I've heard two versions of the same story:
: 1.- It s not prudent to highway cruise at more than
: 2500RPM
: 2.-The same with 3000 RPM as the limit.
: Who's right?
I think a lot has to do with the condition of your truck. If you have an old flat head that is worn, then 2500 is more than enough. I think that if you have a well BALANCED flathead it will handle the RPMs better. I encourage all who have a flathead and some money, to fully balance it when you rebuild the engine, since most of us dont know the entire history of our trucks. It is not uncommon to find parts that are not stock, or modifications to a PW. Someone may have been through your engine before, changed a rod etc, so balancing is of a premium if possible. I have even gone so far as to port mine. I cant say it helped since I am still building my engine.