fuel mileage
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Elder User
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From: midwest
fuel mileage
im looking at an 85 f150 with a 351w. its an auto with 4wd, regular cab long bed. with a small 4 barrel (600 holley) do these get fair mileage or will i be dissapointed? i currently have a 460 in a 78 and its rough to drive with gas the way it is and i also want a 4wd. please let me know what i could expect for 60-65 mph driving. also what gears are usually in these stock?
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From: Virginia
The gears vary according to how it was ordered. The gears and the type of tranny it has will determine the fuel mileage you get. With the best combo of gearing and overdrive tranny, don't expect anything over 15mpg with a 351w.
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From: Hawkeye Country
I have a 351 [4V-HO] in my 86 F150, I can manage 13.5 - 14 mpg going 55 on the interstate. Mine has a old 650 holly on it, it'll really drink the gas when floored, but she does pretty well when I keep the secondaries closed.
As for factory gears I've seen quite a few with 3.50s, and quite a few with 3.08s. I'm not sure if its a standard combo but most of those I seen with 3.08s had 8.8 inch rears, while the others tended to have the good old 9 inch rear.
When I bought mine it had 3.50s with a broken limited slip, I replaced my 9 inch center section with a new unit that had 3.73s and a locker. The 3.73 gear works very well with the powerband of the engine, and the auto trans.
When I bought mine it had 140,000 miles, the guts had blown out of the front cat and plugged the second, it was barely running. I added headers and dual exhaust, I ditched the EGR and smog pump, I bumped the timing up and gave her a good tune up. It runs like a raped ape now, I think you'll be happy with a 351. Mine will run away from the 302 in my 96 F150, and it blew the doors off the basically stock 460 in my buddies 76 F250.
As for factory gears I've seen quite a few with 3.50s, and quite a few with 3.08s. I'm not sure if its a standard combo but most of those I seen with 3.08s had 8.8 inch rears, while the others tended to have the good old 9 inch rear.
When I bought mine it had 3.50s with a broken limited slip, I replaced my 9 inch center section with a new unit that had 3.73s and a locker. The 3.73 gear works very well with the powerband of the engine, and the auto trans.
When I bought mine it had 140,000 miles, the guts had blown out of the front cat and plugged the second, it was barely running. I added headers and dual exhaust, I ditched the EGR and smog pump, I bumped the timing up and gave her a good tune up. It runs like a raped ape now, I think you'll be happy with a 351. Mine will run away from the 302 in my 96 F150, and it blew the doors off the basically stock 460 in my buddies 76 F250.
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From: Asheville, NC
My '83 averages around 10 mpg. That is vastly better than when I got it with all the vacuum lines that were leaking.
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From: Virginia
Originally Posted by Holmesuser01
My '83 averages around 10 mpg. That is vastly better than when I got it with all the vacuum lines that were leaking.
I wonder if you have 4.10 gears if you get that or lower mpg empty. Or possibly a blown power valve in the carb?
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I was getting 7mpg and I redid the carb. Just did a 137 mile (round trip) to pick up a 16' trailer, averaged about 10mpg. So, not quite sure what I'm getting empty, but it's a 1985 250 4x4. Don't know what gear ratios I have since the axle code on the door jamb doesn't match anything published.
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I have an 85 351w also 4 wheel drive with less than 47k original miles and im getting maybe 8 mpg I am in the process of having the Holly changed out to an Edelbrock including manifold also taking off all the unneeded vaccum hoses. I am told this should improve my MPG to 12-14.