Don't Want To Waste Money (at Least Not Too Much)

Hey all,

I'm starting my CJ5 build!! I was given a 73cj5. It's got a 258 (I'm thinking the previous owner might have put a stroker kit in it, not sure but it's FI for sure), t19, dana 300 and a decent lift. Both axles have ARB's. I want to turn it into a rock crawler that's still mostly street worthy. I'm thinking 35's is the largest I'll go. I've got a list of stuff that I want to put on it over time, and I think I've got a good order figured out so that I can drive it in between upgrades and see what should be done first. However, there's one thing I can't seem to find a good answer on.

It's got a d30 up front, and I'm not sure that it'll handle the 35's fully locked while rock crawling. I'm hoping it will though, 'cause I'm not sure that I want the expense of a new front axle. One of the first things it needs though is some disk brakes - I've seen trains that stop faster than this thing! If I get a disk brake conversion for the d30, is there any chance that I can save some money later on a d44 and have those same brakes work on it or is that not an option?

Any other advice on the build is welcome!! I've done lots of jeep work in my life (previous jeeps include YJ on 33's, TJ on 35's, JK on 35's and I've not got a gladiator on 37's), but this is the first time I've worked on stuff that other people have modded before me. It's been a big challenge so far and I haven't done much to it yet at all.

 

From what I has seen, most breaks in the diffs is some what driver related. If a tire is bouncing up and down, when it is in the air it will spin fast. When that tire comes down and hits the ground and stops spinning, that is when something breaks.

 

You'll need to cut the fenders for 35s, or put it so far in the air that the tires never enter the wheel wells. The rear opening is about 34" in diameter, and the interference on the front is the leading edge at the bottom of the fender.

If you must have that large a tire, you can cut the rear and go tube fenders in the front. If you move the front axle forward to clear the rear of the fender, likely you will catch the leading edge of the fender and you'll still need tube fenders or to crop the front.

The factory 11"x2" Bendix brakes work fine if they are in good condition and you use organic-shod shoes. They will fade and do not stop well when wet. Drilled drums are an option, though there are several ways to get disks in the front.

I don't think it's realistic to stroke a 258. The stroke is already very long. Sometimes the 258 crank is used to stroke a 4.0L from later years. Look at the engine code and build date stamped into the engine block to identify that it's actually a 258. These Jeeps came with a 232 or 258 inline 6 and a single barrel Carter YF carburetor. The 4.0L had its own native MPI, and could be swapped in entirely.The T-19 and D300 are not factory equipment, and a different engine could have come along with those. Check the TSM for engine ID.

Just FYI, this is the wrong area for a '73. That's an intermediate Jeep, and they have their own area.

Welcome from Boston!

 

There is a '74 TSM here - Jeep® Parts Manuals online

A '74 is very very close to a '73. IIRC all that changes for the CJ are colors, badges and emissions. Only for the CJs though.

Look at section 1A for build-date code. If you have a 4.0L of some type, it should not conform to the '73 marking scheme. Then check the later books on that site.

 

Thanks for the help! I'm planning on running tube fenders for sure.
Maybe I'll just have to look at servicing the brakes, but with 35's, I think I'd still prefer disk brakes. I know the T19 and D300 are non-original. Lots of Advanceadapters plates on the thing!
My uncle owned it for about 20 years, he got sick and then passed away. It sat for about 10 years and now it's mine. I always recalled him saying that it was a stroker and since I found a few stroker kits (making it a 4.7), I assumed that was what happened - no idea though.

The engine block reads '512a15.' According to the TSM you linked, it means it comes from a 75. the dash sticker is still in place and says it was built Dec of 72, so it's not the original, but the 'A' should mean that it's a 258.

He had a few jeeps, and all the other ones I know had new or rebuilt motors from jasper engines (and the others were all supercharged). My guess is that he got this one rebuilt and tried to squeeze every extra ounce of power out of it that he could. Not sure what that does for the longevity now, but it sure leaks a ton from quite a few places.
I'll make sure the next thread is in the 'intermediate.' I thought I had put this one there, my mistake.

 

A build date of 15 Dec 72 is squarely in the middle of the 1973 model year. That's 512A15. "5" is 1972, not 1975.

A stroker uses a 4.0L block with a 258 crank to make a 4.6 or 4.7 liter displacement. You would be increasing the stroke of the 4.0L with the long stroke of a 258 crank. There is no easy way to increase the displacement of a 258 using the 258 block.

 

As far as the disc brakes are concerned , I think that the only thing is that your Dana 30 has open knuckles , so the Dana 44 would have to be open knuckle design also.

 

Many owners here run the 30 successfully. It's considered a significant upgrade to the 25 or 27 closed-knuckle axle that the '71 and earlier CJs came with.

35s and 37s are popular with the Wrangler crowd, I presume. Not sure there's much reason to go that large with the short wheelbase and narrow track of this era CJ-5. If you want a 44 with the same track width, you'll have to buy it custom built. Expensive.

JMO - it pretty much is what it is. It'll go lots of places without any additional mods. Maybe the Wrangler is a better fit to your ambitions.

 

I have a JKU on 37’s with a D30 and have not had any issues. I’m running a lunchbox locker. That said, I heard the D30 in the JKs is stronger than the older D30’s, but not sure how much truth there is to that.

 

Try the jeep as is, mine has 32 inch skinny tires and will go almost every where the larger lifted newer ones go. the limiting factor tends to be wheelbase. Some things are too steep to navigate safely without risk of tipping. In those cases I use the winch to keep the light end on the ground.

 

Have a good reading.

Green Hell...the Never Ending Project

I can say i have a beast in trail and a caddy on the road. But it invole heavy modification over time.

 

I would say there is not big difference with a jk and a cj dana 30. Jk you have unit bearing, CJ you have full floating bearing (better the full float).

Jk axle are know to have weak tube that bend easily with doing mid-trail. Cj with a 3/8" is stronger.

Jk dana 44 are stronger than any dana 44 than any jeep before. They have 33 and 35 spline instead of 30.

 

I would just run 33s

Better looks, safer on the street, easier on the brakes axles and steering components, still crawls everywhere, fits the fenders better

 

^^^^^^^^
This ~

 

My .02 worth of thoughts. If your set on 35's by all means go for it, I ran 35's on my flatty for years, no it was not stock not even close. I can tell you this though, your biggest issues will be your rear driveshaft and front axle shafts. First the rear, most generally with the 84" wheelbase you have to not only open up the opening the top of the fender needs to be moved up also to allow for optimum wheel travel with minimum lift. Axle drop out will be limited by the driveshaft capabilities. I think there is more to be gained with a motor/trany mount lift than a tall suspension lift since you have no problem cutting the body. The Dana 30 can survive with some throttle management. The joints on the CJ 30 are smaller(260 vs 297)than Wrangler 30's after 93 I believe.

 

I'm not sure that I'm capable of doing all that - and I know my wallet isn't it!!!



I'll have to consider the 33 vs 35 difference more than I thought. I was pretty set on 35's - but with another jeep on 37's, maybe this one doesn't need to be quite as big.

 

On my 73 I am running 35 x 12.5 Swamper LTB with a 2" spring lift and 1" body lift. They do rub out wheeling but do not get torn up. No cutting on front or rear fenders. They were a good choice for off road tires.

 

I just ran the Rubicon with no issue on 33"s and a Dana 30 up front with discs. How long a Dana 30 lasts is typically directly related to the weight of the drivers right foot. Discs are pretty easy to do on a narrow track 30 using GM brackets and calipers, and a Jeep rotor, and will transfer to most similar vintage Dana 44 axles. As others have mentioned, a Dana 44 would be a custom built axle. Most start with either a chevy or full size jeep wagoneer axle and narrow it accordingly.

35's will likely require a bit of trimming. In my experience even 33's can touch a little with 2.5" of lift on an intermediate CJ. They are very capable on 33's, but I also own a flatty that is very capable on 35's with a Dana 30 front. I just have to be aware when I'm wheeling it where the limits are.

 

33" on a cj5 is equivalent o a Tj' on 35" or a Jk 4 door on 37"