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Looking for overall build advice - drivetrain and gearing

Sendero

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Sr. Jr. Member
Joined
May 12, 2022
Messages
63
Hello and thank you for reading, I am new to the forum and my lifelong dream of completing this building is finally kicking off this fall as I have the funds for the entire build. I'll save the sentimental portion of my build for the chat forum but want to go ahead and get some technical opinions out before I start ordering the wrong parts. In short, I am rebuilding an all original/stock '66 bronco that I will never sell, therefore I am less concerned about keeping its stock value and more concerned about nice upgrades which make it cool and functional. I am looking for a weekly driver than can be driven a few hours in all weather. I would also like to do some light off-roading but nothing too serious. 80% street and 20% trails. At the most, I am looking to do some of the easier stuff in Colorado and Moab. I am looking to be cost efficient but am also not looking for a low budget build either. I want a quality bronco that does well at a cars and coffee. Feel free to interject any opinions toward any part of my setup. Below is my current plan:

- Fuel injected 302 out of a 92 mustang I already have (the body of the car burned but the motor is salvageable), I will then have the motor rebuilt into a 347 stroker. Mild cam and tune to be streetable.
- NV 4500 Transmission out of a dodge 4x4
- Power steering
- Power disc brakes
- Air conditioning
- 2.5 inch lift with bilstein shocks
- 16" or 17" wheels 33" tires

My questions are:

- Will the stock Dana 20 transfer case suit my needs or do I really need to upgrade to an NP201 or something? Either way I will have costs associated with rebuilding it or ordering a new/rebuilt transfer case.
- Will the stock Dana 30 Front Axle suit my needs or do I really need to upgrade to the Dana 44? Do I need lockers? I have never minded manually locking the hubs? Not sure how all that works.
- Should I go with a ford 9" in the rear? I would imagine I want posi trac in the rear
- What gearing would be best for the use I am looking for in this rig? 4.10? 4.56? With a NV4500 on 33", I am looking for 5th gear to be a somewhat decent highway speed cruising RPM.
- What gas tank options are best to have more fuel than the tiny factory one? I know there are some auxillary tank options?
- I am looking for decent handling. Are there some trac bar, shock, stabilizer or coil over upgrades that are worth it?
- How far do you think a budget of 40k will get me considering I plan to pay someone 10k-15k for body work restoration?

Thanks for all the help!
 

SteveL

Huge chevy guy
Joined
Jun 24, 2001
Messages
11,608
Loc.
Hawthorne ca
First off welcome aboard. For the motor I would go 351w but if you want to go with a 302 I would sell that one and grab a late 90s explorer 5.0. There are advantages to the efi and front dress of the explorer. The explorer od tranny also bolts right in wit it unless You're sold on a manual. For the front end if you're gonna dump any $$ into it like disc brakes or a locker I would put the money into a 44.
9" rear is fine or possibly look for a big bearing 9". If you plan on 33s under it 4;56shoud be good with an od tranny.
 

Yeller

Contributor
Bronco Guru
Joined
Mar 27, 2012
Messages
5,881
Loc.
Rogers County Oklahoma
As for dollars I'm not a good influence or reference because I purposely don't keep up with it and depending on mechanical tools, abilities and even geography can cause it to vary widely. That being said I'll sick with being an influence. One at a time.... all my opinions....

Gearing I'll throw a wrench out there, with that combination I'd do 4.27/4.30 gear, with a SBF, 33's, 4.10 and over drive can be a bit tall, especially at altitude and 4.56 is just a bit too much. Dana 20 should be fine, I would upgrade the rear output to a 32 spline unit but that is all besides a twin stick conversion.

A Dana 30 will probably be fine for your explained use, but a 44 is superior in everyway, there is a reason Ford upgraded. If you feel the need for a traction device an Eaton True Trac is the only way to go for your uses

Yes a Ford 9" with large bearings, 31 spline axles and an Eaton True Trac limited slip

For handling any of the suspension systems offered by any of our bronco vendors is what I would do. If you really feel like diving deep, Duffs dual sport rear link kit is awesome.
 

DirtDonk

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Bronco Guru
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Nov 3, 2003
Messages
47,345
Most discussions of upgrading the 9 inch in the rear is assuming you don’t already have a big bearing 9 inch in the rear.
That was a factory option and very common, so you may already have what you need in that regard and only need to upgrade the axle shafts and differential carrier assembly.
Agree with the Trutrac comments.

With the NV4500 you are probably going to want a body lift. So factor that in when choosing your suspension lift, in order to keep the total lift within your hoped for range.
If no body lift then expect to cut quite a bit of the sheet metal out of the tunnel to fit the much larger transmission.
At the very least a 1 inch body lift will help with your under hood clearances for the EFI components and a little bit for the transmission.

Most of all, have fun!

Paul
 

Yeller

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Paul brought up some good points. Also unless your looking to not have cut rear fenders don't fall into the tall lift trap, shorter lifts are so much easier to deal with in every aspect. Me with 33's..... 1" body lift, so your factory style injection will easily clear the hood, cut the fenders and do stock replacement springs from Wild Horses, IMO they are the best spring. 2nd in line, and its splitting hairs, is Duff, nothing wrong with either one. Of course geography should play a factor. If your west of the Rockies, Wild Horses, East of the Rockies, especially east of the Mississippi Duff's. Your location would help us help you;)
 

DirtDonk

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And pictures! We’d love to see pictures of this keeper.
 
OP
OP
Sendero

Sendero

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Sr. Jr. Member
Joined
May 12, 2022
Messages
63
All,

Thanks for the quick responses! I am currently traveling and don't have any pictures with me but I learned to drive in this truck when I was a kid at the deer lease. My dad had spray painted it camo and made it hunting vehicle. Fortunately it is nearly rust free as it spent most of its life in South Texas. I live in Central Texas and it will mostly stay there. Yeller, when you say "tall lift trap" are you considering a 2.5" lift tall? I am not a big fan of lifted vehicles in general but want a nice level off road look that fits somewhat beefy tires. The fenders are already cut and they will stay that way.

For some clarity:
- I am sold on an manual transmission
- I appreciate the explorer engine recommendation. I plan on putting a either GT40 intake and heads on the motor or something aftermarket like trickflow.

Long story short, the mustang was a convertible 5 speed 5.0, was my first car, and very sentimental to me. I hung onto it all this time and it was in really good shape. The bronco was dismantled and was a rolling chassis with a new lift, fuel tank, brakes etc installed and in the process of being assembled. An electrical fire broke out at the shop and completely torched the mustang and fried all of the new components on the bronco. Luckily the bronco body was in another shop and is in great condition. The best I can do is use the motor out of the mustang and finish out the bronco. I am not 100% stuck on using this motor but it sure would be nice to have a piece of the foxbody back on the road.

Cheers!
 

DirtDonk

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47,345
I hear you on the sentimental part. Let the Phoenix rise from the ashes!

Do you already have the 4500? If not there might be other options out there as well nowadays, though the 4500 is an excellent truck transmission with a low first gear.

With a transmission that has a low first gear and a tall overdrive, I don’t think you can go wrong with either the 4.30 or the 4.56 gears.
Do you know what gears are already in the bronco? With a 66 and a six cylinder, you could literally already have 4.56 gears!
Even with the V-8 you might have 4.11 gears. And if you have either of those I would wait until you get the tires and the transmission installed and then just drive it for awhile. Just to see how you like what’s in there. Then you can make a better decision on what gears will keep you happy for the rest of its life.
 

Yeller

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Rogers County Oklahoma
I also should have said Welcome to the family! Lol great bunch of folks here that will help you in ways that are unbelievable. Lots of open books of bronco and fabrication here that will share everything they know.

No I don’t consider 2-1/2” to be too tall. I am a fan of low lift/big tires, often to the point of silliness. My personal bronco is no lift on 37’s. Lower lifts drive and perform better in every way unless your into crossing swamps
 

Apogee

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Nov 26, 2005
Messages
6,033
Sendero, for a driver like you're describing, I think there are better 5-speed transmission options that will shift less like a truck transmission, which the NV4500 definitely is...and to be clear, I like the NV4500. In fact, I'm in the process of putting one in my EB now since I already have it from my '77 F150. Prior to pulling it out for the EB, I ran it behind my 429 powered F150 for about 15 years, so I'm fairly familiar with how they drive, and it's a glorified 3-speed truck transmission with a granny low and a OD slapped inside the tailhousing.

If I was building your rig, I'd be looking at the NV3550 or more likely the AX-15 swap, as those are cheaper and more plentiful. Alternatively, the Mazda M5OD could be a decent choice for the type of use you describe. While you'll lose the granny, first will become usable off the line and these should shift a noticeably quicker and smoother than the NV4500.

Welcome to forum,
Tobin
 

nvrstuk

Contributor
Just a Bronco driver for over 50 yrs!
Joined
Jul 31, 2001
Messages
8,604
Welcome aboard!! Sounds like a fun build for sure. :)

For reference I drive mine appr 150-200+ miles/week. I wheel it hard also.

I can't imagine going back to a ZF (which I ran for 12 yrs) or 4500 like Apogee was saying. Glorified 3 spd. 80 percent on road means rowing a truck trans btw stoplights which gets old. I loved it for what it was but you if you really want to enjoy your Bronco on the street then you might want a more streetable trans- makes driving FUN instead of just driving a truck! Closer ratio 5 speed really helps give you more choices for gearing also.

Dana 30 might hold up. IMO, go 44 as was said earlier. Much stronger, discs available (cheap and easy) and if you go on trails in Moab or other places where you will lock up the front end I highly recommend the D44. Nothing like javing a D30 & stripping teeth off a R and P on your first trail with good traction or snapping off those tiny kingpins on a D30. Good traction makes torque and it finds an outlet like axles, ujoints, ring/pinion, D20 output shafts (and other internals) etc. Doing it right the first time is a lot more fun than rebuild/replacing parts after every adventure off road (or on road).


Exploder 5.0 stock has a lot more torque/hp than an older Mustang motor. Easily save a ton of money on a good 170,00 mile Exploder motor that will run for decades w/o burning oil. Budget saver here and if 10 yrs down the road you want to upgrade you can easily. Another benefit is the fan/serp setup. Best budget setup you can put on a 5.0 to cool it without issue, upgrades include the alternator to 4G, allows use of an easy to use ps pump.... ALL benefits!


9" will be fine. Upgrade to 31 spline axles like Yeller said. Important!!

Don't lift it too tall ! Squeeze it all in with a 1" body lift and like previously mentioned maybe a 2 1/2" suspension lift or less.

Best of luck
 
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OP
Sendero

Sendero

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May 12, 2022
Messages
63
nvrstuk, what transmission would you go with if you think the 4500 is too much much of a truck tranny? Seems like the NV3550 may be a good choice. Also, it sounds like the D20 likes to break output shafts, any suggestions on the transfer case setup? I am looking for minimal fab work but am also willing to take the time to do it right if need be. I want everything to be floor shifted and manual, not looking for electronic stuff. I am assuming once I am done installing everything I will have to have custom driveshafts built to length?

I am not quite understanding the hate on my 5.0 motor? I thought it was the exact same motor as the explorers except for the top end, which will all be fresh and upgraded when I am done anyway? It has a serpentine, all of the dressings (AC, powersteering, brackets, etc). I was planning on getting rid of the pulley fan and going with dual electric fans and an aluminum radiator. Thoughts?

All, thanks for the great advice and willingness to help me out! I am reading everything and taking inventory.
 

Okie69

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Sr. Member
Joined
Nov 28, 2011
Messages
774
Everyone is just telling you the best way to get to what you want. The Explorer 5.0 has a bunch of things going for it when it comes to Bronco swaps. One of the biggest being the front dress. Yes your Mustang has a full front dress, but the Explorer front dress is one of the only ones that is compact enough to fit in the bronco with the mech fan and still have room for the radiator. Pretty much everything I’ve read says the mech fan does a much better job of cooling in a Bronco because they move so much more air than their electric counterparts. This is all from my research, someone chime in if I’m wrong.

That being said I’m building one with similar-ish goals in mind. I think you’ll find a lot of people will suggest the AX15 transmission swap. Full kits are available from the vendors.

Here’s a handy guide on some transmission options. The AX15 isn’t in there but there are tons of threads on it on here

https://classicbroncos.com/forums/ams/early-bronco-transmission-guide-automatic-options.986/

Another bit of advice that I only discovered recently the search engine in the website can be a little clunky but if you go to google and search your question with “site:classicbroncos.com” at the end it makes finding the right things much easier. So for the ax15 the search would look like

Ax15 swap site:classicbroncos.com

Hope this helps and welcome!
 

TDubya

Sr. Member
Joined
Aug 3, 2009
Messages
381
Loc.
Fortuna, CA
How difficult is it to source the Explorer front dress? Couldn't he use his Mustang long block with an Explorer front?
 

DirtDonk

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Bronco Guru
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Nov 3, 2003
Messages
47,345
Yes.
It's not that difficult here either, since member sandman (is it sandman23?) sells them complete down to the nuts, bolts and front cover.
The only thing that would need to be done with the existing engine might be to remove anything sticking out of the front of the cam gear. There should not be a fuel-pump eccentric on the Mustang motor (already running electric pump by then) but just by way of making sure that the new timing cover from the Explorer will fit flush on the engine block.
You use everything from the timing cover forward and get yourself the best front drive setup Ford ever had available that would still fit a Bronco.
 

nvrstuk

Contributor
Just a Bronco driver for over 50 yrs!
Joined
Jul 31, 2001
Messages
8,604
I mentioned the Exploder because of minimal wear issues with metric rings, efi it's entire life so there is so little wear that for probably less money than buying a front dress and efi to bolt on to your Mustang engine you would have a complete engine, efi, Exploder dress, etc. Ready to run with minimal cash outlay since you (we all- well most of us) on a budget. That's why I recommended it.

Tranny's.... huge can of worms but you like manuals. I used to also. All I ever ran in my Heep and Bronco since 1971. Bronco since '76. I have ran 7 different tranny's in this Bronco. Totally different tranny's in the same rig so it's a good comparison.

My opinions: 3 speeds are good for door stops, truck 4 speeds are good for large shop door stops (remember- my opinion)- especially in windy areas when you want an around town DD, lol (seriously tho, truck 4 spds work but are brutal for a street cruiser when there are other options available compared to 1980 when that's the only option we had. Closer ratio 5 speeds are the only way to go. Larger the gear splits the less fun it is to drive around town. There are several out there and they are usually dependent on the torque of your engine. AX, M5OD, 3550 all have pretty good gear splits and reliability. So much has changed now that you can buy every part to bolt them in.

In my largest build thread I show a pic of a D20 gear compared to a 205 gear. D20's are good little tcases designed for 27" tires, clutch type lockers, engines with 175ft lbs torque and a 3spd with a 3.03 gear ratio. They are 50+ yrs old. It might last for 10 years for you. I know guys still running them and do ok with mild wheeling and 35" tires. Here's a thought. At Moab Safari last week D20 cases were getting pulled out every night at camp. Yeah, every night and the guys were wheeling but all it takes is one trip to some rocks where traction is good and when it grenades on your first day of your vacation it's all over and it might be a year (or five) before you can come back. Disappointing at best., I know firsthand.

I have been running autos now for 11 years. I'd never go back to a manual. I can honestly say I never killed the engine with clutch engagement when wheeling ( I was geared SUPER lowand had a hand throttle that I could bump if needed)- that is not the reason I went auto. I drove manuals every day for 35 years. I went auto for speed of shifting and gear ratios. Until you're in a 4r or 6r auto equipped Bronco with the ability to manually shift it and HOLD that gear in super deep, heavy wet snow or super soft dry sand dune (steep ones) you won't begin to realize the advantage of the auto over any manual.

Just saying from my experience which isn't everyone elses ...

Wish you the best, hope we aren't just confusing you with personal beliefs. lol

The Idaho club that I wheel with sometimes has the absolute COOLEST event every couple years. They get together and swap rigs depending on what you want to experience. You would get to drive somebody elses 4500, or AX or 6r80 or stroker or 5 1/2" suspension or high bolster seats... Nothing like it. Best thing you can do is go for a ride or drive someone elses Bronco with the same setup yoiu are thinking of trying. If you lived closer you could drive mine. You might find out that you absolutely want to stay with a manual or you might think that an auto isn't that bad! lol I shift my 6r manually all day and it is a lot of fun- I just don't use my left leg to do it.

Good luck.

Brian
 
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BUCKWILD

Full Member
Joined
Jun 20, 2016
Messages
350
Loc.
Butte county
With a 347 I would go 4,88 with 33's, the stroker combo will not make much bottom end power will like to be spooled up to be happy (short rod stroker liked rpm) and the dana 30 is questionable. A 9" in the back with a air or zip locker so it drives well and can lock it up when off road, Find a dana 44 for the front
 

EB70

Sr. Member
Joined
Jun 9, 2006
Messages
696
All these guys have been at it longer than me. But I have been building a lot of stuff forever. I would reiterate everything they said. Definitely do the 1" body lift. It is so much easier to work on. I have a couple and the non-lifted ones are a booger to work on and for hood clearance without that additional lift. WH makes a neat integrated kit for that. Also, having used truck 4-speeds in a lot of other rigs, I would not recommend one here. I am doing an AX-15 swap. Just enough crawl, easy to shift and the lovely OD. Also, the Dana 44 is a much better axle, and very easy to upgrade with off the shelf parts.

Regarding my Bronco, I have approximately 3.5" lift overall and I clear 37's. Just my opinion, but it is really easy to over-lift an early Bronco. Obviously it is cut etc.

Have fun. I think you will enjoy the ride.
 

Yeller

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Mar 27, 2012
Messages
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Rogers County Oklahoma
All these guys have been at it longer than me. But I have been building a lot of stuff forever. I would reiterate everything they said. Definitely do the 1" body lift. It is so much easier to work on. I have a couple and the non-lifted ones are a booger to work on and for hood clearance without that additional lift. WH makes a neat integrated kit for that. Also, having used truck 4-speeds in a lot of other rigs, I would not recommend one here. I am doing an AX-15 swap. Just enough crawl, easy to shift and the lovely OD. Also, the Dana 44 is a much better axle, and very easy to upgrade with off the shelf parts.

Regarding my Bronco, I have approximately 3.5" lift overall and I clear 37's. Just my opinion, but it is really easy to over-lift an early Bronco. Obviously it is cut etc.

Have fun. I think you will enjoy the ride.
Over lifting happens a lot, some of it is owner visual preference, many of us here grew up in the 70's and 80's were taller was better. The other driving part is a fear of trimming fenders, if your willing to trim enough, 35's fit fairly easily stock. I personally like the low lift big tire look, but performance wise lower is better. James Duff was decades ahead with Pony Express cutting and channeling the body to make it lower.
 

Nothing Special

Sr. Member
Joined
Nov 25, 2016
Messages
804
On gearing I'll give a little different perspective than what most say. Since this isn't what most say it's less likely to be right for you, but it might be worth considering. I have a stockish 302, an NV3550 5 speed and 33" tires and I really like my 4.10 gears that everyone else says are too tall. And I might even prefer 3.55s. I'm definitely giving up some acceleration, but I like having less "buzzy" engine noise at cruise. And for what I want I'm perfectly happy with the driveability.

On the transfer case I'll throw a high-buck option into the mix. The single biggest change I made on my Bronco as far as improving its off-road capability was the 4.3:1 Atlas transfer case. Do you need that for more moderate off-roading? Of course not. But it sure is nice, especially on steep hills, which there are a lot of in Colorado and Moab.

For lockers / limited slips, I really like the Detroit locker rear and OX locker front I have in my Bronco. Yes the Detroit is a bit obnoxious on the street, but I don't think it's that bad (and I drive mostly on the street too). While I haven't tried it yet, I'm beginning to believe the argument that an automatic locker in the front and a selectable locker in the rear might be the "best" combination ("best" in quotes because there are so many variables that there's no way any one combo is best for everyone). I wouldn't drive that on snowy freeways (but that doesn't seem like an issue for you), and I think the auto locker in the front would be more obnoxious than in the rear (but you aren't using the front axle much with your driving). So if I were in your situation (and I am!) I'd go with one of those combos. A TrueTrac or two would be OK for lighter four-wheeling and definitely less obnoxious, so that's not a bad suggestion. But even in moderate four-wheeling it's not that hard to pick up a tire on Colorado or Moab trails with a vehicle that doesn't flex great (and Broncos don't). And only a true locker will really help when you do.
 
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