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Old Tue, August 31st, 2010, 02:52 PM
osprey osprey is offline
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Join Date: Jun 2010
Location: Phoenix, AZ
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Thank you, Cleatus, for the vote of confidence.

Other things you MIGHT want to consider on the 4.9/300, depending on your location and other factors:

180 degree thermostat- I have tried it in a long term (1 year) test, and do use one becasue of my location in Hell's Foyer (Phoenix), and the fact that I do have hills to climb going north or east of town. I did not see any significant change in fuel mileage with this change, but I did notice that the engine did not get as hot in hill climbing when the ambient air temperature was in the 100+ range.

Gearing- I FULLY believe that the 4.9/300 acts very much like a diesel, and should be geared accordingly. The engine should not be ran over 2000 RPM at cruise (1800 to 2000 RPM at cruising speed gives me the best mileage), and it should not be ran past 3000 to 3500 RPM at any time. This comes from over 100k miles on the current F150, and over 250k on a 300 in a 1955 F100. That explains why I run a 3.08:1 gear in my current truck, and ran a 3.00:1 in the '55.

The 4.9/300 is a torquey little brute, and runs like a little gas fired diesel. If properly geared, and RPM kept in its power band, it will last well over 400k miles with proper maintenance and give great MPG very reliably.
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