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Thread: Ford 390 build for F350
          
   
   

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  1. #1
    jimmyjack is offline CHR Junior sMember Visit my Photo Gallery
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    Jul 2013
    Location
    Petersburg
    Car Year, Make, Model: '48 GMC 1-ton, '71 F350
    Posts
    2

    Cool Ford 390 build for F350

     



    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

  2. #2
    34_40's Avatar
    34_40 is offline CHR Member Visit my Photo Gallery
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    Sep 2007
    Location
    New Bedford
    Car Year, Make, Model: 34 Ford 3W Coupe Replica
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    If you only want to improve mileage, change out the final drive ratio to something more favorable. Say 3.50 to 3.70's...

    Helping the engine breathe can be a dual edge sword in a lot of cases, helping the flow through the heads also can increase consumption and FE's have always been a hungry motor.

    Using the "Other" motor I find replusive.. If you were going to build/rebuild the FE, find a 428 crank and add the edelbrock top end package, heads / cam / intake / carb... but you're gas consumption won't be going down as you'll need new tires more quickly also!!

    And welcome to the club, nice to see you here!

  3. #3
    Dave Severson is offline CHR Member/Contributor Visit my Photo Gallery
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    Car Year, Make, Model: '67 Ranchero, '57 Chevy, '82 Camaro,
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    Welcome to CHR, good having you with us! About all I've ever gotten out of an FE for mileage was in the 12-14 mpg range. Mileage just was not a consideration when these engines were designed!!! Back when the F-250's with an FE engines were the truck to be towing with we had a few different combinations but that was about the best we got----and if you left late for the track and had to hurry, that number would drop to the 8-10 mpg range! Another consideration would be to build the engine for torque and mileage, then put in a Gearvendor's Overdrive unit to scrub off a lot of RPM!

    If the truck's a keeper and towing power along with good mileage is your criteria, I'd suggest save up some coin and find a take-out 7.3L Ford Diesel with a 5 speed behind it! My current toter has that combination and exceeds your 13-14 mpg by a considerable amount, with the trailer hooked up and the AC on! I'm sure such a take-out diesel in your "neighborhood" would be quite expensive, but still probably worth the investment if the truck is a keeper!!!!!
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  4. #4
    jimmyjack is offline CHR Junior sMember Visit my Photo Gallery
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    Car Year, Make, Model: '48 GMC 1-ton, '71 F350
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    Thanks for the thoughts, friends! I agree that a 7.3 would be a good choice for a re-power. The 403 Olds would require some work to replace the 390 and not be as good a choice as a 7.3.

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