Building a 302 or 5.0 for gas milage

Discussion in 'Technical' started by elliot, Jan 21, 2006.

  1. elliot

    elliot Member

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    I need you guys to tell me what you think of my plans for building a gas friendly 302 for my mothers van . We use it for towing the boats witch is about a hour each way to the river . For towing cars and right now its my daily driver untill I get the mav on the road. The van has 3.50:1 gears weighs 5,500 lbs and has an overdrive auto tranny .

    My plans are to put in a RV cam, do some light port work to the heads to clean them up , a 480 cfm autolite or a 390 cfm holley on a stock 4 barrel intake or a eldelbrock performer and put some headers on it if I can find any cheap enough. I would also like to get rid of all the vac lines and wires that are hiding the engine since only half of it is being used right now and none of it will be when I put on the 4 barrel. The only problem is the van uses the same dist as a 5.0 thats all computer controlled even though it has a 2 barrel on it right now :16suspect . I`d like to know how hard it would be to convert it all to a DSII ignition system ?

    Also I`d like to use a 5.0 roller motor I got but I can`t find an rv cam for one any where . Do any of you know where I could get one for it ?

    Thanks :)
     
  2. tim keck

    tim keck truckdrivintrailertrash

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    Just get an explorer spec cam for the roller motor,they weigh a little over 4000.
     
  3. Charlie

    Charlie maverick.to/grabber

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    If you are interested in gas mileage, look at common performance items that increase efficiency. They will make more power AND improve mileage.

    These are items like:

    -Roller Camshaft
    -Roller Rockers
    -Electric Fan
    -Electric Fuel Pump

    etc etc.

    I agree that an Explorer roller cam will probably be a good choice for a truck, and probably fairly easy to find used or new as a take-out from a new short block or something.

    I don't think a 4V carb will do anything to help your gas mileage, although, it probably won't hurt if it's a vacuum secondary since the 2nd barrels won't open unless you lead foot it. Which reminds me- I get really good gas mileage with my Maverick (almost 20 MPG!) if I am on the highway and keep my foot in check. ;)
     
  4. 74merc

    74merc computer nerd

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    My 2v carb got worse milage than my Holley 600 vac/sec or my 4100. I have a few theories as to why, but none really pan out. Most of my changes were performance oriented (aside from the AOD) and gained milage, including my swap from 2.79 to 3:1 rear.
    Don't underestimate headers, I gained milage by getting rid of my manifolds. Anything to help the engine breathe better seems to improve milage.
     
  5. elliot

    elliot Member

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    Thanks for the tips guys !

    I think that a small 4 barrel carb should give better gas milage over the stock 2 barrel . The smaller primaries in the 4 barrel should make more low end torque than the larger ones in the 2 barrel and from what little I know the more low end torque you have the better milage you get .

    I`m gonna call the parts store tomorrow and check on cam pricing :) .
     
  6. sierra grabber

    sierra grabber Certifiable

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    this has always been my qualm with gov regs on american smog and how it is ruining the american car manufacturers. the regs always push towards holding back a cars performance to cut its smog down, while the orient and europe take the engine towards its max performance to cut down its emissions at regular use. my old 73 390 gets better gas mileage than "most" late 70s early 80s american vehicles for that reason alone.my cars mileage jumped considerably when i had it balanced and went to the 4 barrel. it gets better mileage on a long drive or when i can keep my foot out of it though..
     
  7. 74merc

    74merc computer nerd

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    I went from the 2100 to a Holley 600 to a 4100. The primaries were about the same size, the 2100 and 4100 primaries are identical. I used the butterfly valves from the 2100 in the 4100. I do believe they are jetted differently...
    I know with my 2100 I had to give it more throttle to stay at 70mph than I did with the 4bbl.
     
  8. Will

    Will I

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    For the dist you can find one for a 85 mustang, first year for the roller and was still Duraspark2 or get you a older distributer and just swap the cam gear
     

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