I was shocked recently to discover that my 1948 1/2 ton gets about 4mpg. I was expecting better than that.

Here's my setup: 235 bored 30 over, mild cam, offy intake with 2 Model B's and Fenton cast iron headers. The Model B's have been "rebuilt" with the standard kits you can buy at NAPA, but no work has been done on jetting or anything like that. The motor has about 550 miles on it.

Here's my questions. What's the most likely cause of such poor mileage? (Other than my foot, of course.) Power valve? Springs? Jets? Float level?

The truck runs great and has tremendous "gitupandgo". It has one minor problem. At just above idle, it tends to surge a little, which can make the truck jerk if you don't keep steady pressure on the throttle. It idles fine at 600RPM.

(Please don't tell me to buy the Webers from Stovebolt Engine Company or "Model B's suck". I'm interested in fixing what I've got, not listening to criticism of my choices.)

Here's a couple of pics of the engine so you can see the setup: pic 1 pic 2

I want to try and improve the mileage before I drive to Kansas City for the Midwest All Truck Nationals in September, so any hints, tips, or solutions are welcomed.

Paul Schmehl CI 6
geek@stovebolt.com
Stovebolt Staff: Geek