what would i have to do to run 37 on a stock(ish) 1970 fj40 (1 Viewer)

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I am in the process, as others have said it gets spendy. I have soa, cut the rear fenders, fj60 axles, and a ls. The major parts are easy to budget for, it's all the little parts that add up and really screw with your budget. Also I am doing all the work myself, I would hate to see how much it would cost to pay for the work.
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bhsdriller said:
If you want 37s get an 80 series
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Or a Jeep. That way you can throw money at the solutions that other people have come up with that make it turn-key for a Jeep.

40s take a lot of work to make 37s work. A guy locally has 37s on a 4" SUA lift, but has Metaltech front fenders and body cutting to make it happen. He also doesn't drive it on the street.

What are your fab capabilities? Personally I think SOA is best for tires as large as you are talking (or link suspension). Not many shops out there can or like to do this kind of work on old rigs, they'd rather slap a kit and 37s on a Jeep and call it a day. And if a shop can do this work for you, it will be $$. Or investing in your own fab stuff will be $$ if you don't already have a welder etc.

Do you still have the original axles in your 71? You do realize that they are coarse spline birfs and don't hold up well to large tires and lockers? Now you're talking about $$ to swap in new axles, plus lockers, plus suspension, plus tires, plus gears, $$ $$ $$. Better make sure your wallet and abilities can keep up with your dreams.

If you're willing to go through the progression, from 31s, rear locker, to 33s, to 35s, front locker, to 37s, then by all means keep your 40 and go have fun with it. You will learn more about your rig and its limitations as you go. But if you want to transform it NOW into a crawler on 37s and don't have the experience (not saying you don't, but you haven't given us any indication of your background) to support that style of rig, then I say sell the 40 and buy a Jeep. Seems more fitting to me.

Back when 40s were being made 31s were big, 33s were really big. They weren't really built with larger tire sizes in mind, so it takes a lot of custom work to get them there. These days things are different and the modern vehicles (Jeep) are built with that in mind, and you can slap on a kit and go.
 
subzali said:
Or a Jeep. That way you can throw money at the solutions that other people have come up with that make it turn-key for a Jeep.

40s take a lot of work to make 37s work. A guy locally has 37s on a 4" SUA lift, but has Metaltech front fenders and body cutting to make it happen. He also doesn't drive it on the street.

What are your fab capabilities? Personally I think SOA is best for tires as large as you are talking (or link suspension). Not many shops out there can or like to do this kind of work on old rigs, they'd rather slap a kit and 37s on a Jeep and call it a day. And if a shop can do this work for you, it will be $$. Or investing in your own fab stuff will be $$ if you don't already have a welder etc.

Do you still have the original axles in your 71? You do realize that they are coarse spline birfs and don't hold up well to large tires and lockers? Now you're talking about $$ to swap in new axles, plus lockers, plus suspension, plus tires, plus gears, $$ $$ $$. Better make sure your wallet and abilities can keep up with your dreams.

If you're willing to go through the progression, from 31s, rear locker, to 33s, to 35s, front locker, to 37s, then by all means keep your 40 and go have fun with it. You will learn more about your rig and its limitations as you go. But if you want to transform it NOW into a crawler on 37s and don't have the experience (not saying you don't, but you haven't given us any indication of your background) to support that style of rig, then I say sell the 40 and buy a Jeep. Seems more fitting to me.

Back when 40s were being made 31s were big, 33s were really big. They weren't really built with larger tire sizes in mind, so it takes a lot of custom work to get them there. These days things are different and the modern vehicles (Jeep) are built with that in mind, and you can slap on a kit and go.
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I do have some fab skill but I am new and still fumbling around a bit. I work at a auto repair shop so I do have some welding and plasma cutting experience. So ya I’ll probably work my way up there from 33 to save the budget and get the feel for my rig. Also what would your recommend to start out with 33s with a 2.5in lift or a 4in lift.
 
declan mcgrath said:
I do have some fab skill but I am new and still fumbling around a bit. I work at a auto repair shop so I do have some welding and plasma cutting experience. So ya I’ll probably work my way up there from 33 to save the budget and get the feel for my rig. Also what would your recommend to start out with 33s with a 2.5in lift or a 4in lift.
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that’s a gray area and folks go both ways. Ideally I think the CCOT trucks with 4” lift and 33s look better than 2 1/2” OME suspension and 33s and provide more clearance for articulation and chains (important to me for winter time wheeling). Having said that a lot of folks are happy with 2 1/2” and 33s. 4” will be stiffer and feel tippy, so it’s a trade off. 4” will fit a 35 though (At least I’ve seen it) so if you want to jump to 35 right away that’s a way you could do it. Tires may rub though.
 
subzali said:
that’s a gray area and folks go both ways. Ideally I think the CCOT trucks with 4” lift and 33s look better than 2 1/2” OME suspension and 33s and provide more clearance for articulation and chains (important to me for winter time wheeling). Having said that a lot of folks are happy with 2 1/2” and 33s. 4” will be stiffer and feel tippy, so it’s a trade off. 4” will fit a 35 though (At least I’ve seen it) so if you want to jump to 35 right away that’s a way you could do it. Tires may rub though.
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I’ve Been checking out those CCOT 4in lift kits they look pretty cool but what I’ll probably do is 33 on a 4in lift then eventually go up to 35s
 
Have you found a local club/group where you can check out various builds? My impression of the SOA craze a while back was that it was the perfect Rubicon recipe. If you can do the work, go check out what others have done (or shouldn’t have).

Stock springs Over the axle was plenty of clearance for 35s, lots of people also went to 37s.

There is a thread somewhere here just for 40s on 37s. Don’t let anyone tell you how they think you should build your truck. It’s yours. Lots of “purists” here who like to pass judgement.
 
69LC said:
Have you found a local club/group where you can check out various builds? My impression of the SOA craze a while back was that it was the perfect Rubicon recipe. If you can do the work, go check out what others have done (or shouldn’t have).

Stock springs Over the axle was plenty of clearance for 35s, lots of people also went to 37s.

There is a thread somewhere here just for 40s on 37s. Don’t let anyone tell you how they think you should build your truck. It’s yours. Lots of “purists” here who like to pass judgement.
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@declan mcgrath I agree with @69LC I started with a stock 40 and built it up to handle 37s with SOA. It’s fun for the few trips I take now that I have kids. I wish I would have just done a simple SUA lift and selectable lockers. Don’t get me wrong it’s still tons of fun and my daughter thinks it’s her truck (she’s 2 1/2) but it’s not practical anymore for daily use.
 
Bripars40 said:
@declan mcgrath I agree with @69LC I started with a stock 40 and built it up to handle 37s with SOA. It’s fun for the few trips I take now that I have kids. I wish I would have just done a simple SUA lift and selectable lockers. Don’t get me wrong it’s still tons of fun and my daughter thinks it’s her truck (she’s 2 1/2) but it’s not practical anymore for daily use.
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69LC said:
Have you found a local club/group where you can check out various builds? My impression of the SOA craze a while back was that it was the perfect Rubicon recipe. If you can do the work, go check out what others have done (or shouldn’t have).

Stock springs Over the axle was plenty of clearance for 35s, lots of people also went to 37s.

There is a thread somewhere here just for 40s on 37s. Don’t let anyone tell you how they think you should build your truck. It’s yours. Lots of “purists” here who like to pass judgement.
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Thanks for the advice guys I’ll try to find a fj group near me. I can could learn a thing or two about my build and maybe get some help doing it
 
Yeah but 37's are sweet!

100_0284-jpg.195041


That was my 67. Spring Over, 37's, Saginaw steering, built Fuel Injected 350, SM420, E-locker front, ARB rear, flipped front springs, cut rear tub, mini-disc front, Longfield chromolly axles/birf, hy-steer. It was fun, but there was a lot of work.


It still needed work.
Between the chevy engine, SM420 it felt like an old chevy truck lol. Mainly the transmission. It crawled well and would go more places than I wanted to take without big body damage. I cant imagine it with a 2F.


33's and lockers will get you just about anywhere outside of hardcore wheeling. BFG 35's are basically 33's so if you want roll those no worries on SOA or SUA.
I went everywhere on 35's as I did on 37's...and pretty much the same on 33's locked.
Decide how you want to use this. You might get it all built up and not like SOA and 37's.

Same cruiser on 35 BFGs.

poser (Medium).jpg



My wheeling desires have changed, (so has my rigs) So I don't "need" 37's and rock crawling. I'm more of a light trail, exploring, camping some moderate trails. I'm over body damage trails and tearing stuff up.
 
FJBen said:
Yeah but 37's are sweet!

100_0284-jpg.195041


That was my 67. Spring Over, 37's, Saginaw steering, built Fuel Injected 350, SM420, E-locker front, ARB rear, flipped front springs, cut rear tub, mini-disc front, Longfield chromolly axles/birf, hy-steer. It was fun, but there was a lot of work.


It still needed work.
Between the chevy engine, SM420 it felt like an old chevy truck lol. Mainly the transmission. It crawled well and would go more places than I wanted to take without big body damage. I cant imagine it with a 2F.


33's and lockers will get you just about anywhere outside of hardcore wheeling. BFG 35's are basically 33's so if you want roll those no worries on SOA or SUA.
I went everywhere on 35's as I did on 37's...and pretty much the same on 33's locked.
Decide how you want to use this. You might get it all built up and not like SOA and 37's.

Same cruiser on 35 BFGs.

View attachment 2373870


My wheeling desires have changed, (so has my rigs) So I don't "need" 37's and rock crawling. I'm more of a light trail, exploring, camping some moderate trails. I'm over body damage trails and tearing stuff up.
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That is a bitching build man. But u see I’m still in high school right now and working a lot so I think what I’ll do is go for a 4in lift with 35s or 33s I’m just not sure yet
 
declan mcgrath said:
That is a bitching build man. But u see I’m still in high school right now and working a lot so I think what I’ll do is go for a 4in lift with 35s or 33s I’m just not sure yet
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Great plan.

With a rear locker, 4" lift and 33s/35's you can go tons of places. My parents took us wheeling back in the day on 31's and open diffs all over Colorado like @subzali alluded to. Good luck!
 
Yes
declan mcgrath said:
thanks ill check them out also can i only run rears for a little bit until i get some more money
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Yes, you can run front or rear independently of each other. Have a chat to @cruiseroutfit who will sort out what you need. I would be doing suspension before lockers personally, and I'd be doing maintenance before any of those things.
 
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