Gas mileage on a 54 Special?

Doug Thanks for providing insight into your restoration and now you driving report.
Early in 1972 I purchased and refurbished a low mileage 1954 Hornet Sedan. While the car only had 22K miles, the engine had seized during a 17 year hibernation. The former owner had placed the car in his garage one night and suffered a stroke. The car sat there until I recovered it. To bring the car back to operational status, the engine and transmission were removed. The engine was completely rebuilt. It took new pistons, rings, valves, guides and bearings. The bore was increased.060 over stock. The aluminum head was replaced with a NOS steel head and everything reassembled to stock specifications. The engine in this car was equipped with twin H and a recently refreshed Hydramatic was affixed to the engine. After the refurbishment and reinstallation the engine was broken in around town and one fast 100 mile freeway trip. After 1000 miles the car settled into an 18 MPG on the road and 15 MPG in town. Before selling the car I took it on several sustained highway speed (60+ MPH) trips of over 400 miles. The MPG got better and the best I recorded was 22 MPG on a cross country all night trip from Omaha Ne to Amarillo TX. That trip was mostly 2 lane driving at 60+ MPH and after dark. For the record the speedometer was accurate in speed and mileage readings as I had it checked as part of the refurbishment.

What I learned about that engine was:

With a proper rebuild on each carburetor they must be adjusted mechanically and with a venturi vacuum balance gauge. Choke mechanisms for each carburetor must work correctly and be balanced between the carburetors. The linkage from the foot feed through the bell crank, cross links an springs for each carburetor effect carburetor balance. Linkage to the transmission MUST BE set according to the Hydramatic manual. If the transmission linkage is incorrectly set the transmission does NOT spin correctly to meet the internal pressures needed to shift at optimum engine performance points.

The temperature of the engine is critical in achieving optimum MPG. I used a Hudson neck with a late model thermostat which was drilled to allow some bypass. The bypass in the OEM housing was blocked with hardwood plug.

Ignition timing was optimized to my altitude using the Hudson ... back off till it pings instructions and fine tuned with a vacuum gauge and the venturi gauges. The venturi gauges are capable of showing the lean and rich roll off points for Twin-H carburetors. I used two; one on each carburetor and it became easy to tune the twin H to optimum performance for my altitude.
While there is plenty of discussion about the integral parts of the carburetors, it has been my experience that Hudson cars found in a specific area generally have been optimized for that area. That will not overcome the fact that internal pieces will wear and if that is the case, replacement will be necessary to obtain optimum performance.

As with anything used and of older technology, it is essential to base expectations on the performance factors that were achieved at the time that engine was new. I suspect your engine is giving you the appropriate results for the configuration you provided.

Thanks again for sharing.