Newbie posting after 6 months
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Joined: Jan 2009
Posts: 6
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Newbie posting after 6 months
Hi All,
Want to take this time to thank all who have posted topics during the past 6 months. The knowledge I have gained could not be duplicated by reading books. Most posts are very clear and easy for someone like me to understand.
I have a 66 F-350 w/390, 4 speed tranny. It has a dump body and was used by a Funeral Home. It's rough but runs great. It is used by me and many of my neighbors to haul gravel from the local quarry. One of them loaded 5 tons and made it home (I don't know how). I now have a 3.5 ton limit and she seems to handle it without any problems.
My only concerns are the mileage (8mpg) and top speed (50). I can live with them but it seems the engine is racing at 50 with another inch of pedal remaining. From reading the old posts I realize she's old and carrying alot of weight even when empty, but I'd just like her to do a little better on both counts. Seems everything is original except for the headers and flow masters. She has new 17.5 tires all around with 65 lbs of pressure.
Any suggestions as to how to better the mpg or should I just live with it.
Thanks all in advance-
Bob in Georgia
Want to take this time to thank all who have posted topics during the past 6 months. The knowledge I have gained could not be duplicated by reading books. Most posts are very clear and easy for someone like me to understand.
I have a 66 F-350 w/390, 4 speed tranny. It has a dump body and was used by a Funeral Home. It's rough but runs great. It is used by me and many of my neighbors to haul gravel from the local quarry. One of them loaded 5 tons and made it home (I don't know how). I now have a 3.5 ton limit and she seems to handle it without any problems.
My only concerns are the mileage (8mpg) and top speed (50). I can live with them but it seems the engine is racing at 50 with another inch of pedal remaining. From reading the old posts I realize she's old and carrying alot of weight even when empty, but I'd just like her to do a little better on both counts. Seems everything is original except for the headers and flow masters. She has new 17.5 tires all around with 65 lbs of pressure.
Any suggestions as to how to better the mpg or should I just live with it.
Thanks all in advance-
Bob in Georgia
Logistics Pro
Joined: Oct 2005
Posts: 3,785
Likes: 4
From: Mddl A MexCans
Welcome to FTE!!
Well for starters: a basic tune up to be sure all is well, then
1. Consider a recurve of the distributor. And make sure the vac advance is working properly.
2. Tune the carb based on usage. (Read the spark plugs)
3. Set a preferred RPM range to go along with that max load limitation. (or install a governor)
A taller gear in the rear wont likely help out the grunt for a work truck with 3.5 T's on it's back. So the gain of lower RPM's at speed may be a toss up in trade for less knads off the line requiring more fuel to get moving but ? Total theory there, IMA...
Well for starters: a basic tune up to be sure all is well, then
1. Consider a recurve of the distributor. And make sure the vac advance is working properly.
2. Tune the carb based on usage. (Read the spark plugs)
3. Set a preferred RPM range to go along with that max load limitation. (or install a governor)
A taller gear in the rear wont likely help out the grunt for a work truck with 3.5 T's on it's back. So the gain of lower RPM's at speed may be a toss up in trade for less knads off the line requiring more fuel to get moving but ? Total theory there, IMA...
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
I have had 5500 lbs. in my F100 so 10,000 shouldn't be an overload for the 350. I have the same basic engine in my truck that turns 2050 @ 55mph with 3.00 rears. I suspect you have a 5.** ratio that is turning the motor a lot faster. Just mash the gas it will go faster than 50. As long as the fluids are up you aren't likely to over rev the engine in high gear. From your description, sounds like the ol truck will pull a train. 
Follow Bobby's recs on the tune up, and find another daily driver, I doubt you will get much more than 8 mpg. without spending a huge amount of money though.
John
Follow Bobby's recs on the tune up, and find another daily driver, I doubt you will get much more than 8 mpg. without spending a huge amount of money though.
John
