Inline 6 to V-6
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Inline 6 to V-6
My 91 F-150 L6 is a great truck, but I have to think of MPG's! I thought about swapping the L6 to a V6. I had an Aerostar with a V6 that I drove the houind out of and I think it is still going. I have heard the Taurus has the same TANK v6. (???). So, I thought instead of down sizing the truck, maybe get better mileage out of a v6 and still have power to pull my lawnmower trailer and pop-up. The L6 is 4.9 liter. Automatic Tran.
Will the v6 "bolt in". Will it match the bell housing?
THANKS for any help!
Will the v6 "bolt in". Will it match the bell housing?
THANKS for any help!
More Turbo
Joined: Mar 2008
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The issue you have with downsizing is that the smaller engine has to work harder to move the truck, and will cancel out any mpg gains. This works with passenger cars because there isn't as much vehicle to move, whereas with an f-series, there is significantly more truck to get going.
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But guys....I have driven many factory F series v6's that get up in the teens and better on mileage. That was the basis of my thinking. I have always heard the straight 6 will pull a house of the foundation but forget mileage.
My six is fuel injected. I get around 12 mpg in town, maybe 14 mpg on the hwy (w/o trailer). What kind of mileage should I be getting???
THANKS for all the input, and quick too!
Quaddriver, what is the IIRC?
It may be a bonehead move, but can ya'll comment on the mechanics of such a project and experiences? It may not even be practical $$$$ wise. I just like my full size truck, but may trade it in for a Ranger.
Thanks Again!
My six is fuel injected. I get around 12 mpg in town, maybe 14 mpg on the hwy (w/o trailer). What kind of mileage should I be getting???
THANKS for all the input, and quick too!
Quaddriver, what is the IIRC?
It may be a bonehead move, but can ya'll comment on the mechanics of such a project and experiences? It may not even be practical $$$$ wise. I just like my full size truck, but may trade it in for a Ranger.
Thanks Again!
FTE Legend
Joined: Jun 2006
Posts: 31,930
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From: Ottawa, Ontario
There are owners of I6 trucks on here that easily get 20mpg+ hwy and 15-16mpg city. What gearing does yours have? Is it in absolutely top tune with no issues? How do you drive it?
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Fleet Mechanic
Joined: Mar 2005
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From: St Louis
The most direct bolt in V-6 would be the ol' 3.8 v-6. It was used in the early 80's for a short stint in the f-series and used for quite awhile in the mustang, t-bird/cougar, taurus/sable, and areostar with some usage I think in the windstar. It continued to live on as the 4.2 v-6 in the newer F-series trucks but did not have the same bell housing pattern at that point.
If you do decide to go for a ranger, the 4.0 v-6 is rated mpg wise the same as the F-series trucks while the best mileage is in the i-4.
If you do decide to go for a ranger, the 4.0 v-6 is rated mpg wise the same as the F-series trucks while the best mileage is in the i-4.
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Joined: Nov 2005
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From: Lathrop, MO
yobop1, Welcome the world of inline six fans. 
Your not going to find many that will recommend swapping to a smaller V6 from your current I6. The guys around here are more than willing to help you get the most out of what you already have in the truck. You'd be surprised what can be done, even with the often disliked EFI system.
What is the full configuration of your truck as it sits now? 4x4 or 4x2? Which automatic tranny? What gears are you running in the differental? What is the health condition of the engine? What is the health condition of the drivetrain, suspension, brakes, etc? What tire size are you running? If other than stock, has speedometer been recalibrated?
These are just some of the things that impact mileage. There are a few members here that report 20+ highway with 3.55's in the diff and overdrive tranny's. The main thing is to get it in good running order. Then address issues in the rest of the truck that may be adding exessive load and pulling mileage down.
One minor quibble. L6 usually references the older flatheads and I6 references OHV heads.
Your not going to find many that will recommend swapping to a smaller V6 from your current I6. The guys around here are more than willing to help you get the most out of what you already have in the truck. You'd be surprised what can be done, even with the often disliked EFI system.What is the full configuration of your truck as it sits now? 4x4 or 4x2? Which automatic tranny? What gears are you running in the differental? What is the health condition of the engine? What is the health condition of the drivetrain, suspension, brakes, etc? What tire size are you running? If other than stock, has speedometer been recalibrated?
These are just some of the things that impact mileage. There are a few members here that report 20+ highway with 3.55's in the diff and overdrive tranny's. The main thing is to get it in good running order. Then address issues in the rest of the truck that may be adding exessive load and pulling mileage down.
One minor quibble. L6 usually references the older flatheads and I6 references OHV heads.
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Wow! If Ican get mid teens avg I would be happy. I bought the truck used a year or so back. It appeared to have fairly new wires and plugs. The air cleaner looked good.
Maybe I will give her a good tune up, check the timing and see what happens. Not sure on the gearing - I'd have to research. It doesn't "feel" like a low gear. I would much rather have my F truck! And the six is great - just need better mpg and maybe a good overall tune up will do it. I replaced the coil and the control module already.
Thanks for the info everybody! I will update with results.
Thanks also on the correction (L6 V I6) - I din't know that! The truck is healthy over all. Of course it is old and may need some attention in those areas. It is 4x2, AOD tran, stock tires, etc. I start with the tune up and go from there. I can appreciate the "improve what you got" attitude!
Maybe I will give her a good tune up, check the timing and see what happens. Not sure on the gearing - I'd have to research. It doesn't "feel" like a low gear. I would much rather have my F truck! And the six is great - just need better mpg and maybe a good overall tune up will do it. I replaced the coil and the control module already.
Thanks for the info everybody! I will update with results.
Thanks also on the correction (L6 V I6) - I din't know that! The truck is healthy over all. Of course it is old and may need some attention in those areas. It is 4x2, AOD tran, stock tires, etc. I start with the tune up and go from there. I can appreciate the "improve what you got" attitude!
Last edited by yobop1; Jul 30, 2008 at 08:05 AM. Reason: Add comment
Stick with the 300 !