"Wouldn't that mean that the LOWER gear ratio would give you quicker acceleration? If you have a 3.00 differential, it would take only 3 turns of the drive shaft to get 1 turn of the wheels. Theoretically, if you took it all the way down to a 1.00 differential, every turn of the drive shaft would give you a turn of the wheels.".... Ty..Don't get too worried about the terms used for gear ratios. a 3.00 will be more highway friendly than a 4.00. As mentioned earlier, a 3.50 ratio is a good compromise.As far as axle flange it's the round plate that the brake drum fits on that has the lug bolts your wheel bolts to. Maybe someone here can post a pic of their wheel/ tire/flange width combo with specific meas. on each component. Bill

 

Hey Tyler,
I'm not sure why you are considering a entirely new Chassis for $8K. I would go that route if your's is bent - been in a prior wreck, etc. This whole discussion started based on a hunch that a tooth was missing in your rear differential. I don't think I'd spend $8K based on a hunch. There will be plenty of places to spend money on this truck - Why not take your son down to the salvage yard & get the guys to pick you out a nice 9 inch Ford rear end with decent gears in it for $150. Drop it by your favorite mechanic's place & in a day you will be good to go. Drive it for a bit & see what else you want to change. That wood bed looks a bit past it's prime - that's another pretty straight forward upgrade - Lot's of pre-made bed kits on-line.

Ben in Austin

 

Hey Tyler,
As long as we are passing along lessons learned - I'll throw out an observation. If you take a poll of the folks on this forum you will find that the vast majority have trucks that are not running & are in different phases of major de-construction. Once you start pulling them apart they seem to stay apart for a real long time. Take small bites - replace the rear axle/gears, then do brakes or bed, etc. Ripping out the entire chassis is big & you may be out of commission forever.. If you can get it running then fine tune it all the while driving it.... much better. (I went the major surgery route & I've been out of commission for well past a year).

Our truck is also a father/son project - I wish I had left the engine a lot less powerful - I wish I had stayed with just tuning up the 289 we had in there at 190HP vs the 351 Windsor we have with Edelbrock top end for 400 HP. Less power in teenage boys hands might be better.

All the wisdow I've got - Good luck over there.

Ben in Austin

 

The fenders on an F1 have a good bit of extra room, but not unlimited space. So you want an axle with about the same width as the stock setup. You have some flexibility with varying the wheel backspacing.

57-72 F100 Ford 9" axles are the same width as your stock axle so you keep the axle flange to flange measurement of 61.25" or brake drum face to drum face.

The swap is easy. Block the front tires. Put the truck frame on jack stands just in front of the rear wheels. Unbolt the U joint at the pinion yoke. Next unbolt the big U bolts holding the axle to the spring packs. Careful here, it will be completely loose at this point. Roll it out from under the truck, roll the new one in and using new U joints (for the larger axle housing) bolt it in place, keeping the spring over the perches.

Depending on the year you may have to adjust the pinion angle and you do that by adding caster wedges or shims between the spring pack and the spring perch. Find a longer sliding yoke for the slip joint in the driveline (a driveline shop should be able to fix you up). Thats it

quote: "I am still not sure what transmission I have in the truck, but I am betting it does not have overdrive. It is an automatic that was put in back in the 60s or 70s. So a 3.25 or 3.5 would be ok with that?"

With an automatic and its smoother acceleration you could probably even get away with a 2.75.

 

Ben, I have a few reasons for considering a new chassis. Please lend me your wisdom on any or all of them...

1. The truck needs more mechanical work than just the differential. I'd like to change the whole front end too and several other things. It was suggested to me by a couple of people who know what they are doing that a new chassis MIGHT be no more expensive than keeping the old one and MIGHT save time rather than doing all the work with everything in place on the old chassis.

2. I am trying to do this project in 18-24 months rather than 5 or 6 years. So time is a consideration. It isn't the ONLY or even the top consideration, but it is important.

3. I am trying to be honest with myself. If keeping the old chassis is cheaper but leads to more complex/difficult/discouraging/tedious work that leads me to procrastinate on and/or give up the project altogether, then maybe a new chassis is a worthwhile expense. I am trying to figure out how much more difficult the job will be if I keep the old chassis.

Thanks,
Tyler

 

Thanks for that info Ben. I have gotten conflicting advice about what is faster, cheaper, more efficient--tear it all down at once or do things a little at a time...New chassis or old chassis...etc.

I agree with you on HP and engine thing. I am gonna see what I can do about that.

t

 

Thanks mt! I am pretty much getting the picture here. Thanks again for all your help and info.

t

 

I put mine together mostly stock configuration for just that reason: most of the trucks that are sitting after several years are undergoing major transformations in power plants, transmissions and drivelines, suspension, steering, etc. etc

It takes a lot of labor and brain energy to make upgrades that actually work well. For instance you decide to change the transmission to something newer. You need an adapter plate to make it fit the engine. first thing required is to remove most of the original cross member that the pedals/brake master cylinder bolts to and then fabricate something else in it's place. If automatic you've got to lose the clutch pedal which is on the same shaft as the brake pedal. Next you shorten the driveshaft, keeping the u-joints in sync and the angles equal. etc etc

You can see how one change begins a domino process and unless money is no object, most of us have to wait for the checkbook to catch up to the project and that='s long build times.

A stock rebuild is definitely the fastest and cheapest way to go. Parts are easily accessible, you unbolt something and bolt the new piece in the same place with no custom fabrication required. The only guys who will say differently are either dealers or a newbie that has just spent a bundle on his own pile of parts and wants company. (this ought to be good for an argument : )

Changing rear ends is the single exception to the problem. It's easy, straightforward and upgrade rear ends are easy to come by in most areas.

 

Re: cost of the TCI complete chassis vs mod'ing the existing; you can pay professionals to get the parts and install them on the existing chassis. "Snook" on here went this route for similar reasons, and you could ask him, but I don't think that part of it cost him anywhere near $8k. He went the full MII / 4-link /disc brakes / 9" route with many upgrades. In a matter of weeks his truck went from totally stock to completely fabricated (chassis-wise). Not that he's done, but he leap-frogged at least a year. If there are shops you trust in your area, talk it over with them.

 

Hey Tyler,
I won't argue against replacing the entire chassis if you are set on replacing the front suspension. I went the more piece meal approach & just the Mustang II front suspension cost $5K with installation. I think the concern for going with the chassis is it's a long road to get it all back together - you could easily run out of funds or patience before you get to the endzone. From a safety standpoint going the TCI Chassis route gives you 4 wheel disc brakes, independent front suspension & power steering, & a 4 link rear end. Those are all major positives for a young driver.

------------------------------
A less drastic approach would be to throw a rear end in there as it's pretty straight forward & cheap - & hold off on replacing the entire front suspension instead get the front king pins replaced & the stock front end rebuilt for like $800 - $1,000 & see how it drives. Replacing the front end witha Mustang II is a big effort & major surgery - there are a lot of guys on here very happy with a nicely rebuilt stock front end.

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If you can get it running & stopping fairly quickly I'd argue for less major surgery & more tweaks... (This is coming from a guy who did the major frame off approach - it's a loooong road). What's the engine look like? Is it a keeper?

Ben in Austin

 

There are so many good pointers in this thread, and the biggest, and most important one I have seen, is "What you want as an end result." If you are willing to replace the chassis/suspension, then you need to sit down, and decide what YOU really want out of this project. By replacing the frame, you can choose whatever power plant/drive train set up you want, along with whatever kind of suspension. If you want a really nice, low, smooth ride, then a full aftermarket suspension on air is probably the best route. If you are wanting a 400+ HP street machine, then replacing the chassis/suspension will save time, money, and frustration (due to major metal fatigue of the stock frame, and potential frame member failure), in the long run. If I were going to build a nice street machine out of a 48-50 F-1, I would do a full frame, on 4 corner air suspension, 4.10 gears in a disk brake 8.8" independent rear suspension, and built up 331 stroker backed up with a WC T-5. Set that up with some 295 or 325 60 ZR 20's out back, and some 235 55 ZR 18's up front. I'd have it about 3" off the ground up front, and about 5-6" out back. That's me, and that's how I'd do a 1/2 ton street machine. Tons of power, and tons of handling to put it on the ground, where it counts.

 

Hey Tyler,
Just to help illustrate the rear end replacement question - I've attached a picture of the 8.8 axle installed in the back of our 1950 F1 - Notice the spot where the shocks mount to the support - attaching those brackets is the only welding needed.

Ben in Austin

 

Ha ha! Thanks Joe! Sounds like you got pretty excited and carried away there spending my money! Yeah, I have gotten the message loud-and-clear that I need to decide what I want for an end result. And I have done that. But I guess I have not made that real clear because I keep having people tell me that! And no, the big 400+ HP street machine is not our desired end result. This vehicle is for my 14 year old son to drive when he is 16. The VERY LAST thing I want for him is huge horsepower and a 4.10 differential. We hope to redo this truck into a reasonably comfortable daily driver that is above all SAFE for him and anyone around him on the road. We would like to do it in 18 months to two years. We would like to do as much of the work as possible ourselves so we learn and save money and have a sense of accomplishment when we are done. But we are willing to spend a little extra to expedite the process where it is prudent to do so. If this takes 5 years, it kinda defeats the purpose. But if we pay somebody else to do it in 6 months, that kinda defeats the purpose too. Hence my query about buying a new chassis and starting from there. Is a new rolling chassis the right "compromise" between time, money, and my inexperience as a mechanic in order to achieve our desired result of a decent, reliable, comfortable, safe daily driver for a kid?

And incidentally, redoing the body is not a real high priority either. I am convinced that he (my son) will back into something or get into some kind of fender bender in his first few years behind the wheel. Spending $10K on paint and body work for him to screw up does not seem like a great investment at this point. Plus, we kinda like the beater truck look. There is some rust that will have to be taken care of in the typical places in the back of the cab. And the wood bed has had it. Other than that, we can live with body as is for a while.

We are investigating the drive train right now. It has either a 289 or a 351 Windsor in it that I think we can get working, but that is still TBD.

Thanks! Tyler

 

OK, cool, Ben, this is excellent! A picture is worth a thousand words! So did you put in a mono spring rear suspension? Looks quite a bit different than the other leaf spring arrangements I have seen on these trucks. Am I looking at that right?

I get to austin fairly frequently for my work. Next time I am out there I might try to beg an invitation from you to look at your project, if that wouldn't be too much to ask.

thanks again!
Tyler

 

Good info, thanks. Incidentally, my family has some history in your area...my mom's maiden name is Driskill...does that ring any bells?