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Atlas II 3.8:1 with Dana 44 front axle

sykanr0ng

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Aug 11, 2014
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You don't make much sense to me; Dana 60s with only 35 inch tires and only a 302 engine?
That much beef in the axles calls for at least 37 inch tires and a 351W engine or a 351W based stroker.

Or is your plan to waste money and parts?
 
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bgr

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Well the 351W I looked at is 385/420 and the 302 is 375/380. I’m partial to the 302. Moving to the 351W wouldn’t present me with much extra cost. I’m about 80% to a decision on the engine. I apologize if I’m not clear or if I’m wasting money. It’s not my intent to do either which I suppose is why I’m here. To seek wisdom. I fully expect to make mistakes and hope I can learn from them. I apologize in advance for anything that I say which is stupid or nonsensical.

To be clear I’m looking at the ATK 351 vs the ATK 302. Does your feedback apply to a built 302 or a “rebuilt” 302? I had some concerns about mating the 351 to the 4500 which is the main reason I’m leaning 302. I have a 2” body lift so neither are a placement issue.

I understand that 60s are overkill for my use but I dont think they really hurt my design so I was taking a primum non nocere tact there. I believe 44s would be suitable but my inner engineer is saying 60s.
 

sykanr0ng

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Aug 11, 2014
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You need to look at where in the RPM range the torque is produced, which will almost always be lower RPM with the 351W.
The only way a 302 makes big torque and horsepower is with high RPM.
Low RPM torque is a really good thing for a heavy un-aerodynamic vehicle like a Bronco.
If the 302 will bolt to a transmission so will a 351W.

If you are building for off-road use the Dana 60 loses ground clearance due to the larger center section vs the Dana 44, so that means you need larger tires just to keep above the rocks.
If you are building for the street you will spend most if not all your time in 2wd and the Dana 44 is plenty strong enough for that with the small tires you are going to use.
 

Broncobowsher

Total hack
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Haven’t had much time to dig in but looks like the spider gears. There are pieces in there. Everything was looking good and then it wasn’t. This happened after about 30 minutes of driving. Nothing out of the ordinary. I bought this thing from someone who was trying to flip it. Body is in good shape but everything else was a disaster so I picked it up intending to swap out the whole drivetrain. I have a few friends who know a lot about certain parts of vehicles but I have very little mechanic experience myself and spend most of my time reading about how to do things. For the most part it hasn’t been too frustrating. I have more difficulty understanding terminology used which I’m unfamiliar with so I end up down the rabbits hole at times.

Plans. I really don’t have any plan. I might just sell this one when I’m done with it and start over. It’s a great learning process for me as the only other rebuild I’ve done was a 66 vette (327). That was tilted much more towards cosmetic stuff. I was pretty young when I used to gofer with my father when he worked on his vehicles. He passed back in 2003 and now that I have kids I’ve been working on recreating his garage. 66 corvette, 71 bronco, 68 chevelle, 73 pinto wagon (we’ll see about this one). I think I would like to take any of my kids who have interest as they get older on a couple trips. Like trans America , Mojave’s rd, and maybe some of the more advanced stuff.

So. I’m thinking I might try my hand at rebuilding the rear to get this rolling again. Then shop for some 60s and new driveshafts and all the accoutrements. My research is pointing me to keeping a 302 in here but I’m not certain. I’ve been looking at other options. In the end I will put 35s on this most likely. But unlikely larger than that. I have a fitech efi 4 — I got this from someone who pulled it off their mustang. I’m really more of a carb fan. But I might use it if I ever decided to use this for a daily driver. Sometimes it’s tough to keep the carb on the vette in the zone up here in the north when the calendar turns.

So far... so good though. I really do appreciate such thoughtful responses here. Great community you have.

Might want to read up a little on the FiTech. If he is taking it off, it is probably for a reason. Some have bugs that can never been sorted out. You might be picking up someone else's problem.
 

Apogee

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As stated above, and especially with an NV4500, the flatter the torque curve across the RPM band, the more fun the rig will be to drive with that transmission, so of your two engine options, the 351W would be the easy choice IMO. I have a relatively mild 351W in my EB and have driven it in a few different configurations since I bought it 15+ years ago, but wouldn't give up the torque of the 351W for anything except maybe a 408/427W stroker. The latest incarnation of my EB will be F150 HP D44 and 9" (65" wide), 4.88 gears, 37" tires on beadlocks, ATLAS 3.8 and NV4500 which I'm moving over from my '77 F150.

Having driven my '77 F150 with 35's for the better part of 15 years with a NV4500 behind a 429, I wish I had gone with a 460 (or 514 sroker) for the lower RPM, flatter torque curve. The NV4500 doesn't really love to shift above 4500 RPM, and really seems to prefer something down in the 2500-3500 RPM range IMHO. It's not to say that it won't shift up high, just that it seems to take a lot more effort to get it to do so sometimes.

So for what it's worth, while high-revving, high-HP "Mustang" engines can be super fun in a light car like a Mustang, torque is generally more fun to drive in an EB application.
 

DirtDonk

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Haven’t had much time to dig in but looks like the spider gears. There are pieces in there.

Well, bummer for sure. But as said, there's your excuse for some new stuff. And maybe even some fun. But certainly for some good experiencing...

He passed back in 2003 and now that I have kids I’ve been working on recreating his garage.

Even though it's been 15 years now, sorry to hear that. Sounds like he left his impression on you though, and you're going to do the same for your kids. And that's great!
With any luck too, they'll want to work with you on the projects. As opposed of course, to just reaping the rewards of driving a Bronco and/or a Corvette to high school!;D

...66 corvette, 71 bronco, 68 chevelle, 73 pinto wagon (we’ll see about this one).

Wow, serendipity strikes again. Except for the Chevelle (which I would love to have had) we've had the other three exactly. A '66 convertible w/300hp 327 and Power-Glide and A/C and power steering too! Then there's the old, but still current '71 EB. And gotta' love the old Pintos. Had a '73 wagon too. Full windows though, not that one with the porthole window.
Other than being a total dog with piss-poor gear ratio choices in the manual trans, it was actually a great car.
I say ignore the sneers and jeers and twitter-titters, and go for it!

Hell, I've still got the '65 Corvair! Luckily it's got two things going for it. The turbo gives it a little cred when talking to non-believers, and the first thing people see is a late-sixties Chevy when they're trying to figure out what it is. You can definitely see the heritage.
Enjoy your garage/stable for what it is.

I think I would like to take any of my kids who have interest as they get older on a couple trips. Like trans America, Mojave’s rd, and maybe some of the more advanced stuff.

Wow, some bold hopes! Even those first ARE some of the advanced stuff! Although I think I know what you mean. But yeah, my first experience off-roading (after putting it in 4wd in a dirt field around the house (when they existed) to make sure that it worked, was a long weekend trip over the Rubicon. Man, that was an experience! And it's never far from my memory at any given moment to this day 40+ years later.

So. I’m thinking I might try my hand at rebuilding the rear to get this rolling again. Then shop for some 60s and new driveshafts and all the accoutrements.

If you've got the personal time to fiddle in the garage still (with all the other stuff in your life) I would go for it for sure. The 9" is the perfect learning diff to work on. Just like the PowerGlide is as your first automatic transmission build.
Much less frustrating and involved than a Dana axle. Which in themselves are not really that bad. Just more involved than a 9" Ford.

I have a fitech efi 4 — I got this from someone who pulled it off their mustang. I’m really more of a carb fan. But I might use it if I ever decided to use this for a daily driver. Sometimes it’s tough to keep the carb on the vette in the zone up here in the north when the calendar turns.

Nothing wrong with being a carb guy. I am too, but I'm EFI on all my rigs soon. It's just better and more consistent. When it all works!
I'm not familiar with the "EFI 4" model. Is it the "400 HP" by any chance? Or is this an early version of their current setup? Or maybe just the terminology you're using?
Reason I'm asking is that it immediately made me think of the old Holley Pro-Jection 4, which has a "colorful" history to say the least.

Lots of people running FiTech without any trouble, but not everyone is so lucky unfortunately. Any chance you saw your friend's Mustang running and know it's a good setup?

Good luck with it all. But most of all keep having fun.

Paul
 
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bgr

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Learned a lot in the last few months

3.25 is the gear ratio I want in the diffs with 35” tires. It’s just enough granny in first with smooth 3rd and a nice 5th for 70s at 2200rpm.

Looking at stroked 347 vs coyote.

I forgot to mention. Learning how to gear a differential is a series of $250 mistakes and there is an art to spacer configuration that I still don’t grasp.

Also. Whomever said Dana 60 axles were insane was right. I looked at some and realized my mistake. I think Dana 44 front and rear are a good fit.
 
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DirtDonk

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...3.25 is the gear ratio I want in the diffs with 35” tires. It’s just enough granny in first with smooth 3rd and a nice 5th for 70s at 2200rpm.

Not sure where that ratio came from, but it's not reasonable. Typo maybe?
A 3.25 (even if it was an available ratio, which I don't think it is) would put you at roughly 1800 rpm in overdrive, at 70 with 35" (34" actual) diameter tires.
Too low for even a good running EFI engine in a vehicle like a Bronco.

Looking at stroked 347 vs coyote.

Both good engine combos. Stroker is much easier and less expensive to install of course, but both are popular and work well.
But even though they may like 1800 rpm in a car, they won't like it in a truck.
And you want more acceleration off the line in first anyway, right? If so I'd be looking more at the 4.11 to 5.13 range the others have been talking about.

The 4.11 would put you just over 2200 rpm at 70, which a really sweet running EFI engine (or a very finely tuned carbureted engine) would handle. But it would still be happier nearer to 2400-2500 rpm I would think.
And that happens with 4.56:1 ratios.

I forgot to mention. Learning how to gear a differential is a series of $250 mistakes and there is an art to spacer configuration that I still don’t grasp.

Yep, lots of stuff to know and it's a big dance between just right and just wrong in either direction.

Also. Whomever said Dana 60 axles were insane was right. I looked at some and realized my mistake. I think Dana 44 front and rear are a good fit.

Insane as in price-wise? Size-wise? Harder to build-wise? Or just overkill-wise?
And no Dana 44 in the rear. Just in the front. The rear is a Ford 9" and can be built super stout for not much effort.

Paul
 
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bgr

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I started with 4.11. Then 4.86 and realized that was completely messed up so I talked to a guy at a local garage and he said to try taller so I found this place called strange engineering who had a 3.25 gear set for ford 9”. This is with the 3.8:1 atlas 2.

Dana 60s are nice but with 3.5 suspension lift the clearance disappears. I think the 9 is nice and feel like it’s my baby now but a shiny spicer 44 would be pretty slick.
 

sykanr0ng

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Aug 11, 2014
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A Dana 44 rear in a Bronco would be:
1. Need to be completely custom work and that means expen$ive.
2. Weaker than the Ford 9 inch that a Bronco comes stock with and much weaker than a well built 9 inch.

A ratio of 3.25 might almost make sense if you always drive it in low range, but that would suck most of the time.

You really need to stop taking 'advice' from the hot-rod guys that have no idea how to make a Bronco perform.
 

Broncobowsher

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Jun 4, 2002
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He might mean 3.25 effective gearing. OD ratio times gear ratio.

What is the dana 44 rear? The 9" is nearly as strong in the gearset as a Dana 60.
 

Cooper

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A lot of jeeps use a rear Dana 44, I think the Wranglers still do. Nissan used them as well. Maybe your mechanic/friend is thinking about 4x4's in general; i do hope he doesn't think your Bronco is a jeep though %). Ford did have a 3.27 (not 3.25).

https://www.snydersantiqueauto.com/high-speed-ring-amp-pinion.

Does speak more to a hot-rod or cruising / touring realm of thinking and not off-roading at all.
 
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DirtDonk

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Not to take anything away from the guys at Strange, as they've been building Ford 9" diffs to the nth degree for years.
But going to an even taller ratio than stock, with taller tires than stock, and an overdrive transmission, IN A BRONCO, just does not make any sense.
Even with a built 460 you might be bogging off the line and lugging it on the open road. Why put your engine, clutch, transmission and mental health through all that.
Even Ford never offered taller gearing than 3.50 in a Bronco with barely 28" tall tires.

But whatever you do, as I think someone suggested already, ONLY change the rear end ratio to begin with. Don't spend for both front and rear until you know you like the result of the one that does most of the driving. Change the 9" rear to whatever ratio your chosen expert recommends, then drive it for awhile. If it fits the bill, then change the front to suit.
But save yourself the aggravation and cost of doing both until you're sure.

Paul
 

DirtDonk

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I suppose it should be mentioned that the one good point of the lower-numerically ratios is that your 44 pinion shaft will get stronger. Whereas the lower you go (higher numerically) the weaker it gets, until you reach a point of diminishing returns for any given setup.

That's the only good thing I could come up with for gear ratios in the 3.2 range.

Paul
 

Broncobowsher

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I had to go back to the beginning, this thread really bounced around. IS the NV4500 still in the plans, or has that changed as well?

The NV4500 has a .73 OD ratio. For a 3.25 effective final drive, the actual final drive would need to be 4.56s. That would make a lot more sense. Weather that is right or not, I can't say. The engine options throughout this thread are too diverse. Everything from a stock 302 to a Coyote.

Lets back up a little. Make a plan before you buy ANYTHING.
What is your current plan? From crankshaft to tire size and everything between. Maybe we can make sense of it.
 
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