In light of all the inconclusive conversation re "what's a safe speed to run my old Flathead", I'm wondering if any of you have a F-6/F-600 or an F-7/8 flathead truck with an intact or operative factory governor. If so, what R.P.M. is it set to?j

 

What about one of you guys with an old fire truck with a water pump? Those ran continuously running the pump and had to be governed.

 

Somewhere on the Old Car Manual Project Carburetor Manuals - The Old Car Manual Project
there is a manual for governed carbs. I always assumed the desired RPM was set by the throttle cable? Not fixed. But on a pumper I could see it being at a specific RPM.

 

Reading from a 1938 version of The Ford V8 Cars and Trucks Service Manual The Norman W. Henley Publishing Co. page 175.

The standard governor 40-6850B1 is factory set for 2500 rpm. The speed may be adjusted anywhere between 2250 to 2750 rpm.

This would be the 85 HP engine they're talking about.
So if you really want to baby the truck, figure out your engine speed using a gear ratio calculator and drive accordingly.

 

For what its worth my 50 F6 with factory gov even says Ford on it- is gov.
at 3,000 rpms but when hits 3000 it slightly drops to around 2800 rpms.

 

Does it do that regardless of load? In other words, will it run faster empty than when loaded? Sounds as though it wants to fall back up on the torque curve. (The torque curve probably falls off after 2500.)

 

Common for these old vacuum and mechanical governors to overrun the set speed slightly and then drop back. They're reactive and not extremely accurate.