CJ2a Flatfender Build

I've been wanting to start a build thread and have checked out several different sites but I keep finding myself browsing this forum, so I guess I found a home. This is my first Jeep build but I've built a couple muscle cars, some trucks and even a little baja car before. I can design and fabricate almost anything, my little bro is a body man, and I have some buddies that have built jeeps, so I have think I have the bases covered. However, that being said I am by no means the expert so I am open to any advice, critisism or questions anyone has.

What I am building is a 48 CJ2a...kinda. That's what the body tub was born as and that is what it is titled as anyway. It all started with a trip to Durango, CO and a 47 Willys Jeep followed me home. The plan was to make it a modified trail jeep. The more I got into it the more I realized how complete and untouched this little guy was and didn't have the heart to modify it. So...off to storage with the 47 and plan B. I found a M38A1 frame and a 48 CJ2a body on Craigslist for basically free so the fun begins. My goals for this build are:
1. Build it cheap - trail ready jeep for less than $5k. Free parts, Fab'd parts and refurbished parts as much as possible. My labor is free.
2. Make it reliable and safe enough my wife could wheel it with her girl friends on an easy to moderate trail
3. Have it complete, tested and ready for a trip to Mt. Blanca CO by July of 2010. This will be a 1 year build from start to trail ready finish.

I started collecting parts in mid July 2009 and as of today I have the following:
1. 1951-1952 M38A1 frame
2. (qty 2) 1948 CJ2a body tubs
3. CJ2a front clip, windshield and tailgate
4. 305 SBC motor and a TBI system from a 91 Camaro
5. TH350 automatic transmission with NP208 adaptor (bonus)
6. Narrow track D30 front from a 79 CJ5 and D44 rear from a 69 Scout 800a (one piece axles and limited slip) with 3.73 gears in both.
7. D300 T-case from an 80 CJ5.
8. Rubicon Express extreme duty 4.5" lift YJ springs (spring under)
9. 15"x10" aluminum wheels with junk 33" 15.5 Mickey Thompson tires Plan to mount 35x12.5 Boggers on the wheels.

I've been spending most of my time researching and collecting parts. Finally got started a couple weeks ago building. What I have done so far is cut the pieces to box the frame and hung the front axle. Pictures below are my progress so far starting from the beginning.

M38a1 frame, body #1, hood, windshield frame and D30 axle in the shop


Truck o stuff I got for free digging through my dad's stash including a 305 SBC, TH350 Trans and wheels


Body #2 I picked up off ebay including the front fenders, grill and tailgate...all in pretty decent shape. Much better than Body #1 or the 47 body.


Body #2 sitting on the M38A1 frame with the front axle hung.


Realized here that the frame is 4 inches longer in the back than the body.
Think I'm going to stretch the body to compensate just behind the seats...gain leg room too. Turns out the CJ5 was based on this frame so I should be able to stretch the tub to the length of a CJ5 and be able to still put a soft top on it.

 

I like the plan but be aware if you stretch the tub, you will have to get a custom top made. A CJ5 top will not fit the windshield at all. I would just leave the little 5" overhang and make a filler plate to finish it off. Also, that 305 might not fit in the body as it is. If you need to stretch the body, take a look at stretching it in the front fenders so the distance between the back of the grill and the firewall gets the length. that way you can still use the orgional style top.

 

Thanks for the welcome and the comments!

Agree...definitly will need a shoe horn. I know the SBC will fit without mods to the fenders, but will have to take a little out of the firewall to clear the distributer. I'd rather take it at the firewall because I love the stubby flat fender nose of the 2a . I've personally seen 2 of them with SBC's, one guy made just enough room with a box sunk into the firewall to clear the distributer, the other moved the whole firewall back 2-3 inches. As for the entire drivetrain length, ya that's a problem. I'm stretching the rear 8-9 inches to gain me some driveshaft length. The longer frame is actually a bonus to me. I wasn't aware the windshields were that much different between the two...bummer. Thought I had a good idea. Might have to do the filler panel thing.

 

It's going to be tight I definitely agree and if it's not going to work now's the time to make changes. Please check my calculations:

Original T90 plus bellhousing is 16.125" and the original Dana 18 is 10.5 from front mount surface to center of the rear u-joint. That is a total of 26.625"

TH350 plus the GM adaptor is 25" long and the 1980 jeep D300 is the same length as the original D18 at 10.5". That total is 35.5".

So...that means the new trans/t-case assembly is 10.5" longer. I can move the engine forward an inch from the original location and have a 5" longer frame which gains me 6". The plan is to weld on a rear bumper that is spaced 3" off the rear of the frame and mounting the rear spring shackle mounts off the bumper to gain a total of 9" to the rear. I'll then be 1.5" shorter from the rear of the t-case to the diff and will have approx 5" more lift than the original.

Now...because of this the rear axle will not line up with the wheel opening or the frame arch in the rear, the plan is to section the body behind the seats and stretch it 5" to match the M38a1/CJ5 frame and gain leg room (I'm 6' 3" tall). Then move the axle back another 3". Running 35's I'll have to open the wheel opening on the body from 31 to 35, so i'll fudge it to the back to center the opening on the rear wheels new location. The only thing then is the frame arch. It won't be centered over the rear axle anymore. Don't think it is a problem, but this is my first one.

Sorry if this is hard to follow, I think my idea will work. If you see any issues PLEASE let me know! I can make changes now...when I start cutting it's hard to go back.

 

I hope you're not working under your jeep while using the cinder blocks to support the jack stands?

I want to see you complete this thread while staying in one piece!

 

x2

 

Ya...thanks me too, but no reson to get under it yet. Was using them for mock-up purposes. Took that much to get full droop! Still measuring and planning at this state. Thanks for the concern

 

If you are using Wrangler springs, be aware that the extra length of the springs eats up some of the "stretch" you are hoping to get in the wheelbase. I added 6 1/2" to the front frame horns, made a rear crossmember/bumper to mount the shackle hangers to in hopes of hitting 98" on the wheelbase. I ended up at 95" because of the extra spring length. Still an overall 14" increase in wheelbase.

 

Ya...took that into account, made sure I had the springs in hand before doing anything, thanks for the advice . It actually made me go back and double check.

Made a little progress. Built a front crossmember and finished boxing the front frame horns. Was going to cut the horns off and streatch them some, but after some closer measuring I only needed an inch more. This M38A1 frame is quite a bit longer in the front. There was a lip bent from the site to the front for the original bumper mount that was an inch long (how convineint). I heated and straightened them on both sides, this is now the end of the new front crossmember. Used a piece of 2x3 box channel for the crossmember.





The little bro came over and worked on the front fenders some. They looked pretty good until he started grinding the layors of bondo and paint off...yikes! They are pretty rough, guess I would be too after 60 years of being beat on though. Even found a nice hole in the top that was full of bondo. Metal is pretty stretched, probably going to have to cut quite a bit out.

 

Well, it's been a long time since I've posted anything figured I'd give an update. LOTS of things have changed.

The drive train is basically the same with the exception of the front axle. I am now running a Dana 44 front axle from a 78 Wagoneer instead of the narrow CJ Dana 30. Going to the Wagoneer axle brought on some issues. My wheel bolt pattern changed and it's wider. I could use Bronco outers to get 5 on 5.5 but that still leaves me with the width issue. So...excuse to upgrade right? I sold the aluminum wheels and had some Hummer double bead locks re-centered. The tires are now military surplus 36x12.5-16.5. I got some 5 on 5.5 to 6 on 5.5 spacer/adaptors for the rear axle so the track of the rear would match the front. Ended up with 2" spacers in the rear and now it is just a touch wider in the front than the rear. Front measures 62.25 and the rear is 62. This is center to center of the tire.

Now for the frame, I streatched the M38a1 frame so that my new wheel base with YJ springs is 90" and boxed it completely. I also re-inforced the front of the frame. The Wagoneer axle forced me to outboard the spring perches so, due this and adding a power steering box from the same Wagoneer plus a wench, etc... I felt it was necessary, probably wasn't needed but I feel better now.

That's a real quick update. Below are some pics. The first is the motor, trans and t-case assembly. the next 2 are the frame before and after the POR-15 was applied and...drum roll please...the last is my rolling chassis! I have a TON of pictures, so if there is something else you want to see or have questions on...I probably have a picture of it! As always, feedback is appreciated, good or bad! If you see issues, I'd like to know sooner than later...

 

Looks awesome! How long is your rear drive shaft going to end up being?

 

Thanks! driveshaft is approx 22" long, but that is without the weight of the body, cage, fuel tank, etc...

 

I like the design of the outboarded springs mounts.

 

Got the engine running. Had to put a new cam in it because the one it had was really loapy. Only had 13" of vacuum at idle and since I'm fuel injecting it which uses a MAP sensor I need at least 18" at idle. Plus, it's obviously going to be idling along on the trails and over obsticals, barely able to idle is probably not good. Next project is getting the GM TBI setup installed and wired so I sat the tub on it to run the harness and place the computer and fuse block. I put the windshield and a fender on it to see what it looked like... If you look close at the fender you'll see a red spot where I stretched the front fender. Decided to stretch here instead of the tub. This way I can still put a soft top on it. Plus moving the front axle forward so much it looked funny not having the fender over the front wheel. starting to look like something...gave me some motivation.

 

Now that looks wicked