I have a 65 F100 300 six cylinder with a 4 speed. I am looking for engine / transmission swap possibilities that will make my truck more highway friendly. Is it possible to go with an 87-92 or so fuel injected 300 and zf 5 speed? Would a zf 5 or any other 5 speed work behind my current 300 six?
I am just looking to make a little more economical driver out of it.
Thanks for the site and all the information.

 

I don't believe they ever changed the bolt pattern on the 300, so if you get the tranny with the belhousing any year should fit, you may need to make the cross-member and the driveshaft, but that isn't a big deal. The bigest problem would probably be the juice clutch setup. Hopefully some-one here has played that game and will speak up.

I've elected to go with bigger diameter tires and a higher geared front and rear end in mine, much simpler.

 

The early and later 300's are the same basic engine and will physically interchange.
The EFI requires you to use the ECM and all related systems and wiring like in tank fuel pump, O2 sensors, etc.

The ZF trans is doable with the mods stated above.

What is your current mpg and rear gearing?

 

I just got the truck and am not sure of the current gearing. I know that if the speedometer is correct it doesn't like 65 mph. I will try to check the rear for a tag. I have a 74 6 cyl. auto truck chassis with engine, tranny, rear end, power steering and power disc brakes all in place. I plan to check that rear end also to see if it may be higher geared.

 

ASBCPASTOR, Welcome to FTE & the Slicks Forum.

The truck most likely has the smaller 240 engine rather than 300. It was available but not installed like the 240. Trucks weren't driven over about 50 back then. I know it sounds like it is screeming but as long as it is in high gear, just mash the gas, you aren't going to blow it.

An upgrade would be in order for me, and I'd be looking much newer. You have some things to chew on and you will figure it out.



John

 

Thanks for the help. The previous owner had the truck for10 years and told me he bought a newer (? year) 300 six from a friend to put in it about six years ago. How do you identify the 300 vs the 240?
I am thinking higher gears in the rear would be the quickest and best fix for highway speeds.

 

Hi,
I drive a '65 F-100. It has a 240 ci 6. I run 16" rims, the best tires Michelin makes, the rear end ratio I am not sure of. It must be like 3.25 or so. When there is a hill, the ratio slows me down. ( Course so does the hill). I had the rear end put in when I lived in Ga. Pretty flat there. When the temp is 50 deg. or more, I get 17.9/18.3 mpg.
On the Interstate my cruising speed is a cool 70 mph. The engine is happy there. I should tell you that I usually drive as if there were an egg between my foot and the pedal. That helps a lot.
The engine has 158,000 miles on it now. I am very strict when it comes to the 3,000 miles oil/filter/ greasing.
Chat back ifn you wanna, Pete

 

That doesn't sound bad. 17 mpg I could live with.
Thanks

 

Ur welcome,
Please remember: I bought the premium grade Michelin tires/inner tubes. The 60,000 mile tires (16"). I drive with a 4 speed like you have, I think you said.
The tires/inner tubes ran $1300.00, mounted balanced. I get that back of course slowly in good mpg. I am very satisfied with my truck. I don't plan on driving anything else. I have been maintaining/driving my magic carpet, going on 32 years now. I drive 42 miles round trip M-F to my job. The first 11 miles are Interstate and 11 miles are on a four lane. A cool cruise.
Next year I turn 66. I will apply to soc. sec. I will still be working. I will save my s/s $ and use it to have my truck painted and gone thru. It needs to look as good as it preforms.
I am putting split exh mnflds on the engine. This will help reduce the back pressure and I hope to do even better in the mpg dept. I will let you know. It will be several months till I am finished.
Awe righty then,Cheers, Pete

 

Where do you plan to get your split manifolds? Will they be header style? I have wondered what the six cyl. would sound like with a header or split manifold run into a single three inch or larger exhaust.
I need to do the steering and brakes first though...

 

Welcome to FTE Pastor,,, my 66 F100 has the little 240, has the T18 and 3.70's in the 9" I also am running 265/70/15's according to GPS my speedo is spot on and I get 17.5+/- on the flats going to Fresburg and back. I drive it everyday up here in the mtns and avg. 15 and change...main thing would be to check your rear end ratio and maybe up your tire size to match.

 

'87 and up EFI motors used two 3 into 1 manifolds, and they fit without much modification on the older motor. How it sounds depends on what you do with the muffler etc.

 

Thanks again for the help. I will have to consider upping the tire size. I currently have 235/70/15 Coopers on it. I like the way they look but drive ability and looks don't always match up.

 

I'm with you, all 5 on 5.5 that I am aware of are 15", not sure where the 16" comes from. Tire size could make a slight difference, but I just don't see it at the end of the month.


John

 

16" 5 on 5.5 were optional. Many fleet orders used these to run common tires between the trucks.

Garbz