I am having my third member rebuilt locally. While I am at it I am considering going to a ratio that would get better MPG than my current 3.89. What would be the lowest ratio I could go to & not overload my 223ci. 6cyl.?
'63 F-100 223ci. 3spd. lt. duty manual

Thanks for all advice.

 

tgunn, I don't know what they get for rebuilding a 9" where you are in Texas, but 28 spline 9" chunks are pretty cheap (less than a hundred bucks) and swap out in less than an hour. The problem that you are gonna run into with a gear change is a small cube engine in a full size truck. You might get by with something in the 3.50 range but the engine will loose what umpth is has quickly going below that. IMHO

John

 

John- thanks for response. I have seen others say the same thing about going with a used unit. Here in central texas I have not found one for under $200. And, that is with no guarantee that its in any better shape than mine, & finding one in the ratio I am looking for seems impossible.
I was thinking about the 3.50 also. Maybe I'll go with that. I'm still waiting for my shop to tell me EXACTLY what needs to be replaced. Anybody else had any experience with switching gears on a 223?
Thanks

 

tgunn, Do you have your email feature turned on? I'll bet one of your Texas neighbors can shoot you a mail with a lead on one. You are correct, about getting a guarentee with one, most yards in North Carolina will replace a part if it is not right. You should be able to purchase an open 3.5 28 spline chunk for $50-75.00

Your truck engine can't handle anything below that with out lugging it. They have to make rpms to make power.

John

 

I switched my '62 with a 223 from 4.11 to 3.50, and its a dog on the highway. I have to drop to third gear on any steep hill and can't tow anymore.

I only did it because I intend on going to a big block v8 by the end of 06 (and swapped the 9" out for a dana 60 already geared 3.50) but in the interim, it really lacks go.

 

My 61 Uni with the 223 and lt duty 3 speed was factory equipped with 3.70 gears. When (if) I get it running I will be able to tell how well it does.


John Pajak

 

Not to change the subject, but how about keeping the 3.89 gear for speedo and torque off the line and adding overdrive to your 3 speed? That would give you the lower RPM on the highway and keep your low speed performance.
Jus t my .02
Dan

 

the gear ratio won't thrwo off the speedo as long as you run stock size tires which determine your final gear ratio. also o/d is at least 2,000.00

 

What?

Having changed gear ratios on my truck or jeep at least six times in the last year.. that's the most incorrect statement I have heard in a long time.

 

I'd reconsider the swap to 3.50's. They'll probably work, but I doubt you'll see a big gain. You'll end up working the engine harder to get it moving which will use more gas... If you're buying new gears I'd go no less then 3.70... If you get a $50 or $75 chunk that's a 3.50, then I'd try it, but I wouldn't spend the $350+ on rebuilding you're rear and take a chance that you went too high...

I'll bet you'd get more gas mileage from covering up the bed then going to a 3.50 or higher ratio... Just my thought...

David

 

Well, right or wrong, I did it. My Ford 9" was shot. So, I had it rebuilt with a 3.50 gear. So far I like it. The engine no longer sounds like its screaming at 55-60 mph. I will admit that I sometimes have to get a running start at some hills in my area. I have not checked my MPG yet.

I don't use my F100 to tow anything. I just drive it to work 25miles each way, & use it to haul stuff I don't want to put in my Tahoe.

What is it about these old trucks that makes me feel I've made a good investment when I have spent about $3k on a $1500 truck?

 

Because you are fairly sure you'll still be driving that $4500 truck in 10 years. I bought mine for $2250 (4x4, costs more) in 1991.. I'm still driving it. It served as my daily driver a little more than half that time.

 

It's not realy about how much you poor into it, it is all about how much fun you have driving it.

Am I right?

jd