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July 2007 4x4 Tech Questions - Tech Line

Posted in How To: Tech Qa on July 1, 2007
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Address your correspondence to:
Four Wheeler
6420 Wilshire Blvd.
Los Angeles, CA 90048-5515.

All letters become the property of Four Wheeler, and we reserve the right to edit them for length, accuracy, and clarity. The editorial department also can be reached through the Web site at Due to the volume of mail, electronic and otherwise, we cannot respond to every reader, but we do read everything.

Question: I just got a '53 M38-A1 Jeep, and was told that it is basically a CJ-5 but for the military parts. I was wondering what body parts (bumpers, lightbars, roof racks, lift kits, and so on) are interchangeable between the two models. I have been looking around and have found lots of stuff for CJ-5s, but not for the M38-A1. I'm planning to put on a new bumper to hold a PTO winch and a few lights, then add a roof rack, and eventually a snorkel. Those are just the big things-a lot of little upgrades are planned too.
Kyle Arras
Entiat, WA

Answer: Yep, you've been told right. Actually, the CJ-5 was based off the M38-A1 that came out three years before the first CJ-5. The differences? Just off the top of my head, there is the 24-volt electrical system that is pretty much waterproof, a stronger frame, higher spring rate, a battery box in the cowl, a lower dash that is known as a "knee knocker," no tailgate, different front fender mounts, a grille that's hinged at the bottom, a hood cutout for a snorkel, water shut-off breathers on the gearboxes, and I'm sure others that I have forgotten to mention.

Will stuff for the CJ-5 fit? Generally, yes, or can be adapted to fit. Yes, the suspension uses a greaseable shackle and eye, but this is easily converted to a bushing style, and the front spring shackles are the "reversed" style, unlike the CJ's. (OK, the first couple of years of CJs had reversed shackles up front.)

Question: I own an '03 Ford F-350 Super Duty 4x4 Crew Cab longbed. My problem is the truck wanders on the road, especially if I run over an uneven road. I have taken it to two Ford dealers, and they said it's per the specifications. Is there any off-the-market steering gearbox that I can buy and install out there that will cure this problem (to me it's a problem)?

This truck is my fourth truck and I don't have a plan to buy another one. I had no steering wandering problem with my '94 GMC 4x2, my '97 Dodge 4x2 1500, or my '02 Dodge 2500 4x4 when I had them. Somehow, I just cannot accept what they are telling me about my 350. Now the warranty is over for the front end, and I have to put out the money to get it right. Please help, I need your advice, and I want to keep this truck. It's my retirement truck.
Lito L. Delacirna

Answer: It's probably too late now to get it, but the alignment machines that the dealers and most shops use are capable of printing out the alignment information both before and after any adjustments have been made, and they will compare them to factory specifications. My guess is that they didn't show you copies of these. Did you actually have the service manager drive the vehicle with you, and let him verify that there was a problem? Most likely not. I would push the warranty deal and tell them that it was never fixed right under warranty and you are not happy. Hopefully, they will fix it right.

My guess is that it's not the steering box, but something else. Could be worn tie-rod ends, loose wheel bearings, or even the tires themselves. You need to figure out just when the wandering started. Maybe after you changed the tires to another tread style or brand? You just may end up taking it to a shop that specializes in frontend alignment and have them check it out. Be sure to tell them exactly what the truck is doing and under what type of driving conditions, and that the Ford dealers that worked on it said it was OK. I have seen instances where, due to production tolerances stacking up on the negative side, that factory specifications on an alignment don't always work out. Best of luck, and let me know how it works out.

Question: I've been reading your magazine for a few years now and just love it. First off, those who write in and complain about way too many Jeep articles and tech info can shove it. The way I look at it is that it's obviously who is doing the most writing in requesting the info, so just follow the trend!

What is the proper way of setting up dual carbs on my Chevy 350? All that is done right now is a set of Edelbrock headers, an MSD ignition, dual 231/44-inch exhaust with 4-inch jet boat bottles on 3-inch tips. The truck is an '85 Chevy 31/44-ton 4x4 regular-cab longbox with an 8-inch Skyjacker lift with reversed shackles residing on 44-inch TSL Swampers, with 4.56:1 gears on Dana 60s. I like the 350 that's in it, but just need to squeeze a li'l more power. Would there be any benefit to putting on a Six-Pack, or are there other solutions other than dropping a new engine in?

Answer: Well, to start with, you're right. The majority of the letters we get are from Jeep owners, and the majority of the vehicles on the trails are Jeeps, but that doesn't make us Jeep-biased. That's what our sister magazine, Jp, is for: "just Jeeps." We try to cover all vehicles.

Anyway, what's really hurting your performance are those 44-inch tires and only a 4.56:1 axle ratio. That's about the same as running a 31-inch tire and 3.23:1 gearing, but worse! Worse because the truck also has to push much more air out of the way due to the lift and the added rolling resistance of the tires due to more contact area as well as their weight. You actually need an axle ratio in the 5.38:1 to 5.86:1 range, as this will put the engine back into the right rpm range where it can develop some horsepower and torque. Changing to this new ratio will make it feel like you added 100 hp to your engine.

As for the dual carb setup-well, you pretty much have the correct carburetor right now with the four-barrel Quadrajet. It's an excellent all-around street and trail carburetor. Most likely, it needs a complete makeover to bring it back to a performance level. One place to check out is i-5 Automotive (800/526-9952, for a replacement or a rebuild of yours.

I believe you could pick up an honest 10-plus more horsepower by swapping over to one of the performance manifolds. Edelbrock has its Performer that's good from idle to 5,500 rpm, and the RPM Performer that produces power from 1,500 to 6,500, if you should decide to go with a cam change. Weiand's Action Plus and Holley's dual-plane are also good choices. If you don't want to keep your present carb, Holley's Truck Avenger works quite well. Just make sure the manifold you pick will match the square-bore bolt pattern. I have used both a modified Quadrajet and the Truck Avenger, and found them both to work quite well-even on steep sidehill angles.

As to your question on dual carbs, well, with modern manifold design, it has been found that a single four-barrel will generally outperform both dual four-barrel and multi two-barrel carb setups, plus you don't have all the linkage hookup problems.

If you also think that you want to make a camshaft change for even more horsepower, be sure to make the axle gear swap first. If you think that your truck is underpowered now, going to a performance camshaft with your present gearing will almost make it undriveable. Whatever you decide on doing, don't "over-carb" or "over-cam" thinking that bigger will be better-in most off-pavement situations, it's not.

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