My '78 crew has a straight six from when I bought it, it has power but no get up. The gears in the reareand on it are 4.56

 

My guess would be 14-15.I am hoping mine improves with a tune, but we'll see. The way I look at my old trucks is that they are fun to drive. When I worry about economy, I drive the economy car

 

Agreed. I'm getting around 14-15 with my truck. 300 4-speed. I have no idea what gears are in it, but my truck has plenty of power for me. If I want to go fast, I jump in the 'Vette or Nova.

 

I have a 79 F350 dually with a 12' Dump on it and a 300 I6 motor. The engine is real wore out but still has the power to get a load moving and bring it up to highway speed. It gets about 14mpg loaded or not. My nicer 78 with the exact same setup but a 400 V8 gets 9MPG. Guess what one gets drove more!

-Jim

 

I have a 79 f250 2door longbed 4x4 bought her in july 2010 and it also has a inlinet with a 4spd granny.mine gets around 6-8 miles to a gallon.these ole trucks dont do great on fuel but hey they look great and are eye catchers. you cant go wrong with the inline.so in if your lookin for a solid motor you should go with a inline 6.

 

You need to get your answers over at the I6 forum. I have an F350 that I swapped from a 390 to a 300. My goal was to retain the hp, but yet achieve 50% better mpg.

I now get 17 mpg on the freeway with 3.31 gears and a C6. Before I got 10, rain, shine, empty, loaded. I am now packing the nuts away so I can swap it over to a ZF five speed manual. Not only will you get better mileage with a manual, but you'll regain about 30 hp.

Changing over to the 300 worked out great for me.

 

Anybody have any suggestions on what is best year for the inline 6 300, mods that can be done, cam to use, etc, etc. Looking to build from scratch or find a good doner.
Thanks.

 

decades ago i built up a 300 I6 from a early 80s and stuck it in a 1970 F250 4x4 that i put the running gear from my old 77 4x4 under , it was a nice truck got done with it and it got stolen after about a year ! put steel timing gears in it !

 

There is loads of info available at the Inline section of this site. Also try fordsix performance.com. The first thing to do is to decide what you want your engine to do. I mean do you want it to turn 7k rpm, or just make a good daily driver with a pair. Once you know what you want, then you start buying the parts to get there.

Good luck.

 

There is loads of info available at the Inline section of this site. Also try fordsix performance.com. The first thing to do is to decide what you want your engine to do. I mean do you want it to turn 7k rpm, or just make a good daily driver with a pair. Once you know what you want, then you start buying the parts to get there.

Good luck.

Well to begin I di enjooy your choice of words, "or just make a good daily driver with a pair"....... I have to stop laughing. But in fact that is what I plan to build, good daily driver with a pair. Any suggestions??
Thanks.

 

Sorry for spelling errors...............DUH

 

My belief is that stock-ish is best. I wouldn't do too much except maybe chevy rockers and EFI manifolds along with a good tune up. They choke these engines from the factory, but for a low RPM driver you don't need extreme flow.

 

Using the Chevy rockers can be a can of worms. It moves the p.rod closer to the valve, and can rub if not set up for it. IMO it is always better to get the extra lift from a nice cam, and leave the v.train geometry alone.

The nice thing about the 300 is that you can about double the hp and retain nearly the same mpg. If you want to see some nice gains, you have to start with the head. It is the bottle neck of the engine. It needs to breathe easier, to flow more. That is done with a simple $350 porting job, cleaning up the bowls and runners, polishing the c.chambers. With that add a 30* back cut on the intake valves to a 3 angle v.job, and you are taking a major step to waking up your engine.

Add to that a nice Offenhauser intake, and a good 4v carb, and the efi exhaust with dual 2" or 2.25" pipe, or single with 2.5" pipe, and you will have quite an engine.

I have a series of articles about how to wake up the 300 in true blue trucks magazine, and write a column for them called backyard mechanic.

Good luck.

 

Have a 300, 79 F150 4X4 short bed in about 1000 pcs at the moment, I have had it since 1980. I am on my second engine with a total of 250,000 plus miles on the truck, Would have rebuilt the first on but scored almost new one for very cheap. 15-17 MPG all the time, hwy or town. I do not think much will out pull it locked in and 4lo. Current work is getting my 79 F250 4X4 in for paint, its a long bed two holer and needed a new bed real bad. Super nice forum.