I am swapping a 460 into my 79' Ford Pickup. I'm looking at putting a cam in it(not a big prostreet cam), K&N intake with *extreme filter, new Holley carb, splitfire wires and plugs, and maybe new rockers. I also have a big C-6 tranny. Will also have headers and flowmaster muffs.
The engine is out of a 78 Mercury Marquee and is a *low compression* 460. If somebody could estimate for me, what kind of gas mileage do you think i might be getting when i make the swap? Also, if anybody has any suggestions on what other small "adjustments" i could make, i would appreciate it.

 

I haven't done this myself and you don't give much detail on the truck, but extrapolating from my experience with other cars and my 94 F250 w 460...

I would estimate you will be lucky to get between 8mpg and maybe on a nice day 13mpg. I get 11-12 mpg on freeway with no load on my460 FI engine. If you have an F150 which is lighter, I would expect towards the higher end.

A lot depends on what cam, what Holley etc and what you are trying to achieve.

If I was doing this, I would also consider a good intake manifold, what kind depends on what you are doing. The intake can give you good mileage and low end torque or it can give highend HP or a tradeoff somewhere between.

I would probably lean towards a torquey kind of setup since with a truck and most day to day driving you want torque at the low end to get your butt moving. I would also go a bit conservative on the tube size of the headers. Small tubes make better torque, big tubes make better HP. High HP numbers are for the guys with light cars and high gears who like to wind it up. A nice RV cam with a good dual plane manifold would be good, maybe with a Holley 750 sized carb. I think Holley also makes a carb with tiny primaries and huge secondaries, you might check that out since that would give good mileage and throttle response with a good reserve for high end power.

I don't know if anyone still makes the manifolds with two separate intake runners to each port(Offenhauser was famous for this), but that would be a good setup for good mileage and torque with reasonable high end HP. If you looked inside an offy manifold you would see two rectangular ports, one small and the other fairly large. Same concept as the Holley I mention above.

Of course if you have a nice lightweight F150 with high gears and want to race, that is a different story.

Hoep this helps.

Jim Henderson

 

hey, just a little note save your money and just by regular motorcraft plugs for your motor. gas mileage and power will not be that much more your going to notice, plus spending over $40 for plugs. just my 2 cents, been there done that. C.J.

 

I think on my 460 I get in between 6-10 most of the time. The block is a '71 so it has a shorter deck height than the later models. I have a 750cfm holley on mine. Youc an always up the carb size for more power!

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1985 "Cowboy Cadillac" Ford F-250 4x4, Granny 4-speed, 4:10 Gears, 460 with Holley 750cfm 4-barrel Carb, Custom Painted Block (Ford Dark Blue), Rebuilt Transfer Case, BFG Trac-Edges, Tachometer, Kenwood CD Player and Pioneer Speakers, 27" cherry bombs dualed out each side with 2 1/2 inch pipe, NAPA Premium Clutch, NAPA Premium timing Chain, Gooseneck Ball, Hitch Reciever, Whistler 400 radar detector!

"When in Doubt GAS it"