Hi Gentlemen,

I've studied this Club HOTROD site and believe there are some very savvy engine builders here, including a professional or two. Here's my question: what are your thoughts for my building a good performing Ford truck 390 that will balance fuel economy with performance? The F350 is a low mile truck with the following: 12' Napheide flatbed, dual wheels, Dana 70--4.10, C6 transmission, stock everything. The 390 runs great, even with the horrible FE exhaust manifolds and Motorcraft 2 bbl. It flies down the highway with ease but won't pass a gas station. I don't drive it with a heavy foot most of the time. We're paying about $4.60 / gallon for regular gas in Alaska. My plan is to throw the FE exhaust manifolds away and replace them with Sanderson headers. I'm not sure about the rest. If I could achieve 13 or 14 mpg with a more modern cam and Edelbrock Performer or Performer RPM intake manifold, I'll consider spending money on an engine upgrade. I'd like to choose a reliable and efficient carburetor. Any thoughts on a good efficient 4 bbl carb for this application? I've installed a GM HEI style distributor and that is a good improvement over the worn out points distributor. With this 6,600 lb truck, I'm seeing 8 to 10 mpg now. Another possibility for a mod is to stuff the 403 Olds I have hanging on an engine stand into the F350 with a 400TH bolted to it. I realize many folks laugh at the 403 Olds but its a mild performance build and it made my old Trans Am fly down the highway with a steady 16 mpg. In dad's motor home, a 403 Olds got a consistent 10 mpg. They are good torque motors and perhaps have combustion chamber and manifolding design to achieve a bit better fuel economy than a similar cubic inch Ford FE. Do any of you guys know that to be a false assumption? If any of you engine builders with extensive experience have any sound advice, please let me know and don't be afraid you'll offend me--that's not possible. Engine building for a very specific application isn't exactly an exact science and theories with no experience to back them up have little appeal to me. Thanks for any thoughts, friends!!
--jimmyjack