I have searched and read a lot about the swap but I couldn't find any help with my Question.

I currently have a rebuilt(3 to 5k) with holley pro-jection, DUI distributor and borla SS header. I'm in search for more power and I'm thinking of the 4.0 head swap. I would go with the MPI but I would loose all the money on the parts mentioned above. My question is has anyone ever done the head swap and ran the pro-jection with the 4.0 head? Would it be worth the hassle to do the swap without going MPI? Putting a newly rebuilt 4.0 head on my silghtly used long block won't hurt anyting will it? I know I will have to get a new header but everything should bolt up right? thanks for the help:D

It would be a really good upgrade with any 258. The only thing to concern yourself with is the bolt pattern on the intake manifold. I dont know for sure if the 258 intake wil bolt up. The performance of the 258 head is :barf: . Is the pro jection tunable? (i've never played with that) If so, it would prolly love the better breathing motor.

My 4.0 head install (http://gripguru.com/mods/gine/40head.html)

go to: home.att.net/~jweir/jeep/head/questions.htm He says it's a bolt on. Must use 1/2 head bolts. The intake bolts on, exhaust manifold needs to be a 4.0. Use the 4.0 head gasket.

the 4.0L intake and 4.2L intake have different mounting holes. The pins on the 4.2L are closer to the ports than on the 4.0L as you can see on http://monsterslayer.com/jeep/40Head/40Head.htm an aftermaket carb intake might have both but a stock one would have to be redrilled to be milled or grinded or filed to fit the 4.0L head. a small round file might to it with some elbow grease.
http://monsterslayer.com/jeep/images/ManifoldBoltOn.JPG

Originally posted by gripguru
It would be a really good upgrade with any 258. The only thing to concern yourself with is the bolt pattern on the intake manifold. I dont know for sure if the 258 intake wil bolt up. The performance of the 258 head is :barf: . Is the pro jection tunable? (i've never played with that) If so, it would prolly love the better breathing motor.

My 4.0 head install (http://gripguru.com/mods/gine/40head.html)


I have already read your wright up:D How has the appoxy held up? The pro-jection is tunable so that won't be a problem

In most cases you CAN mount the older OEM 4.2 and aftermarket 4.2 intake manifolds (FI or otherwise) on the newer 4.0 heads.
The biggest hurdle in doing so is that you have to pay particular attention to alignment to avoid leaks due the difference in port shape and the absence of the correct alignment pin configuration.

So the best set up would be a 4.0 intake and exaust manifold to bolt up to the 4.0 head. Then all I would have to do is make an adapter plate to bolt up the holley pro-jection to the new intake:D

Yep.

PM me if you need any of the 4.0 HO manifolds. I have extras ...

Originally posted by TOY 2



I have already read your wright up:D How has the appoxy held up? The pro-jection is tunable so that won't be a problem

It is at 7500 miles so far and never a hiccup. I also ran some "block seal" in the motor after the initial break in. I got it at the vatozone, its in a cardboard cylinder(like pillsbury biscuits) with a orange and blue label.

What year is the 258 block? If its not 80-83, you should already have the 1/2 inch head bolts.
What type of Jeep do you have the engine in? If its a full size, the 4.0 intake will not fit because of the big power brake booster.
Also trying to modify the 4.0 intake for your projection might be a bit involved if your not a real good fabracator.
The 4.2 intake will fit on the 4.0 head, like in the picture above, you will need to mount the intake above the little head intake studs. You grind a little off the bottom of the intake stud holes and keep test fitting untill you get a good cover of the intake ports, grinding a little at a time. You will also need to use the 4.2 intake gasket, this has a little more gasket than the 4.0 gasket and will seal better.
Once you get all that fitting real good, you will either need to get larger washers (also seen in the above picture) for the intake bolts or make your own. The little 4.2 bolt "washers" will not be large enough to hold the intake and exhaust. You can use the larger dia. washers with the rest of the 4.2 hardware to mate everything up.
As you have read in all the write ups on the net, you must use the 4.0 exhaust manifold or get a header for the 4.0. What they don't tell you is that you also need to get the "cross over" pipe for the 4.0. Thats the part of the exhaust pipe that connects to the 4.0 exhaust manifold goes under your tranny then down the passenger side to a cat. You can get it at a yard or I got mine from a-zone for about $35.00
The biggest thing is the extra water ports that are in the 4.0 head. Some people close these with J-B Weld then file down or get the head "decked". You can also weld them closed or have 3/4 inch freez plugs machined into them. Then again, I have found a few AMC car sites that have not tried to close these water ports at all and just used the 4.2 head gasket instead of the 4.0 head gasket to seal the ports. Kind of like some Chevy engines, if you have good solid metal on the block where the water ports are on the head, a good head gasket and new head bolts will keep the ports closed themselves. The few AMC guys that have done this have been running their engines for 1-2 years and a few thousand miles without any problems.
Faund a AMC racing web site and they talk indepth about the 258, 304 and 360. I think horse power and tourque wise, a good 258 is just about the same as the 304, stock that is, but done right, a 258 can leave a 5.0 and a 304 behind.
I have done the same thing (duh) and should have the engine back in my full size Cherokee by next week. I'm also running a HEI dist, MSD heli coil wound 8mm wires, and a motorcraft 2100 2bbl carb. Next thing is trying to get some 4.10 axles that I can just bolt right in.

Originally posted by gripguru


It is at 7500 miles so far and never a hiccup. I also ran some "block seal" in the motor after the initial break in. I got it at the vatozone, its in a cardboard cylinder(like pillsbury biscuits) with a orange and blue label.


If you have an 88-90 YJ 258 block you avoid the water jacket problem, because these years of 258 block share the same wide-deck as the 4.0L block casting.

87 is a crossover year so an 87 258 should be checked (early or late production YJ, or SJ, can be different blocks).

The earlier CJ/SJ 258 blocks must be checked for the water jacket port conflict with the 4.0L HO head. These blocks have a less expansive deck surface that allows the water jackets in the head to be exposed.

Using epoxy for water jacket sealing has been reported as hit and miss: with the 87-90 block owners finding success, and 86 and earlier block owners complaining of long-term leakage and cooling system pressure problems.

Be aware of the differences in 258 block construction and apply your efforts to address what you are working with.

Happy Trails!

Has anybody thats done the swap used "Hard Blok" Water Jacket filler I have read Jaffer's write ups as well as many others and have never seen this stuff mentioned. I was wondering if it would be worth a shot or if it seems like it is a waste of money

Jegs LInk (http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1798&prmenbr=361)


http://www.jegs.com/photos/772860212.jpg

although I am doing my swap on a 90 block so if what Ed says is true I guess I would not have to worry to much about it. I have never read that before on the research I ahve done so far

Originally posted by Pyagid
... although I am doing my swap on a 90 block so if what Ed says is true I guess I would not have to worry to much about it. I have never read that before on the research I ahve done so far

True, little has beens said about early YJ blocks.
Good info, Ed. May I post it in the 4.0 head swap article?
Though I kind of doubt as many as you say have had trouble with the epoxy ...
I've had scores of good results and only two or three disapointments on record out of the hundreds of swaps that I expect have been done.

Originally posted by Zorm
As you have read in all the write ups on the net, you must use the 4.0 exhaust manifold or get a header for the 4.0.

It sounds like you're working on a CJ. I swapped a 4.0 H.O. head onto my 86 CJ's 258. Keep your Holley Pro-jection, and DUI dist. and run that with your 4.2L intake.

Use a factory 4.0L exh. manifold. I used one of a '98 Rokee. I had bought a Hooker Header for the 4.0L, but it won't fit with the 4.2L intake. Buy the looks of the pictures I've seen, most other 4.0L headers WILL NOT work with the 4.2L intake. For the CJ, you won't want or need the "downpipe" as mentioned. But you will need to fab up your own or have a muffler shop bend one up for you(simple). The 4.0L head and exhaust also does not have provisions anywhere for EGR. Keep that in mind. You will also need to have an O2 sensor bung welded into your new downpipe, as the 4.0L exh. manifolds don't have one.

I don't know much about the Holly Pro-jection system, but I wouldn't run anything but MPI on the 4.0L intake. If your running a TBI (or carb), stay with the 4.2L intake( I'm putting a GM 4.3L TBI onto my 4.2L intake w/ 4.0L head, and did a lot of research into this).

The intake ports on the 4.0L head are larger than the 4.2L intake. I used a die grinder to enlarge the ports on the intake and port matched the whole set-up.

I should finish and post my head swap write up. There's more, but I'm tired of writing...


http://members.shaw.ca/foreweb/head_11.jpg

I want to hear more about your set up when you get done. How did you come up with the idea of a GM 4.3 injection on the 258?

Originally posted by Jaffer


True, little has beens said about early YJ blocks.
Good info, Ed. May I post it in the 4.0 head swap article?
Though I kind of doubt as many as you say have had trouble with the epoxy ...
I've had scores of good results and only two or three disapointments on record out of the hundreds of swaps that I expect have been done.


Feel free to post the information regarding the YJ 258 block casting difference: the fact these late 258 blocks share the 4.0L casting molds and the same wide deck surface (that mate to the 4.0L head without exposing the water jacket ports).

We did a 4.0L head swap onto a 85' 258 back in 1999, with a Mopar MPFI conversion kit, and we found the problem with the water jackets. We were as confused as anyone, as the monsterslayer head swap web page offered no mention of the problem (since changed). I traded e-mails with the monsterslayer article author and learned they had not completed an actual head swap (at the time) and I was given names of others who had completed the swap. The continued research found the swaps referenced were either welded heads, HESCO or Clifford heads, or head swaps on top of YJ blocks. When we called HESCO and Clifford they understood the problem, and only offered their modified head (with furnace welded water jacket ports) as the solution. This exercise led us back to the junkyard, where we looked at YJ 258 blocks and identified the different (square sided) deck, identical to the 4.0L block. This is how we found the difference with YJ 258 blocks.

Since we already had the 85' 258 block prepared for new pistons, we went back to our machine shop and asked for advice. The experience of the machine shop (JMS Racing Engines, Monrovia, CA) with AMC six engines, and the head sealing problems common under race conditions, provided considerable input leading to a solution. An agreed goal was to minimize the potential for heat related head distortion (a problem with furnace welding or threaded and shouldered plugs), a concern that lead to the solution we ended up using.

The machine shop came up with the solution of machining reliefs at the exposed water jacket ports to fit flat 7/8-inch freeze plugs. The solution required no welding, no excessive machining (not like threaded plugs), and maintained as much head deck casting material as possible to prevent potential heat distortion of the head surface (to prevent the problems associated with the material removal required to fit shouldered freeze plugs).

The 258 HO combination we built may never achieve sustained rpm where lifting the head off the block can be a problem, engine speed past 5500 rpm, but the possibility that the engine would experience high temperature operation for extended periods of time (Baja sandwash and beach running) elevated the concern with the sealing method, and the resulting solution.



http://members.aol.com/Stvns/4lhohe1.jpg



This engine has experienced no problems with head sealing or the water jacket ports.

Happy Trails!

So what is a flat freeze plug, are they like the other freeze plugs, and are they as common as the other freeze plugs????Where is the stress relief? That is just a flat round hole drilled into the water jacket right???? Hard to tell from the pic.:confused: :confused: :confused: :confused: :confused:

Originally posted by Ed A. Stevens

I traded e-mails with the monsterslayer article author and learned they had not completed an actual head swap (at the time) and I was given names of others who had completed the swap. The continued research found the swaps referenced were either welded heads, HESCO or Clifford heads, or head swaps on top of YJ blocks. When we called HESCO and Clifford they understood the problem, and only offered their modified head (with furnace welded water jacket ports) as the solution.


Ed, thanks for adding your experiences to the pool of knowledge!
I'm that "monsterslayer article author" and I do recall our conversations back when.
At that time Tim Weaver was putting the Question and Answer formatted article together and he'd just got his up and running using the epoxy method. I offered to add pics, and convert the article to HTML and post it on my Monsterslayer (http://www.monsterslayer.com/jeep) site where it remains today. And I still try and keep it up to date with new input such as yours.
Shortly after the article was posted in 1999 I bought the furnace welded Hesco model since I had no head and wanted a new (and relaible) one anyway.
I've stayed in touch with Tim over the past few years. He is into Enduro Racing but his son still drives that Jeep with the epoxied ports and I still drive (and compete in) mine.
Neither has given us any problems with the jackets.
Again, thanks ... and Happy Trails to you too!

Originally posted by GPERX4
So what is a flat freeze plug, are they like the other freeze plugs, and are they as common as the other freeze plugs????Where is the stress relief? That is just a flat round hole drilled into the water jacket right???? Hard to tell from the pic.:confused: :confused: :confused: :confused: :confused:


They look like a flat slug with a slight convex curve (no flange shoulder like a "normal freeze plug).

Flat freeze plugs are not that common (we ordered them).

Stress relief is having a creative machine shop :) to work with. "Relief" is a throw-away term used to describe machining to remove a minor amount of material.

Yes, a flat round hole fly-cut (a little like precision drilling) into the deck surface. The bottom of the hole is flat for predictable maximum sealing surface area. The hole depth and edge are precise to provide a tight seal as the brass plug expands under a temperature increase.

I cound tell you more, but I've been told before that the PBB is not the place ;) for rocket science.

Jaffer, it's been good to watch the web page(s) grow in detail and content (and to hear that Tim Weaver is still active).

Happy Trails!

I would like to know from the guys who have used the Epoxy where you find water dissolving peanuts? How does this hold up to heat/cold. I live in MN and it gets below 0 here a few times a year.

I'm going to use an epoxy called SeaSpar. I used it in the intake ports of my Harley and it worked fine...2 years so far.

Im going to reuse my 4.2 intake and carb for the time being, but what about the tube that goes between the exhaust manifold and the intake manifold on the 4.2? it obviously is no longer used when the 4.0 exhaust manifold is put on (I have one from a wrangler BTW). Doesnt it have something to do with the EGR valve and emmisions stuff? I need some direction as far as drilling and tapping the exhaust manifold or what ever I need to make this legit for PA inspection...

I'm new to this porting stuff on the 4.0 head but how much of the hump at the intake port can be ground down?????

upj, the tube you are talking about is for the EGR and needs to be retained in order to keep the vehicle smog legal. This means you will need to weld a bung into the new 4.0 headers for the EGR up tube. FWIW, you may also need to weld in a bung for the O2 sensor as well, if your application requires one. Check their size and thread before you put them in as they are different from each other.

I have done several of these swaps and have used Clearwater Cylinder Head (http://www.cylinder-heads.com/)for a head already welded and ready for this swap. They are familiar with the swap and are reasonable in price (around $400 for the complete head, rebuilt, welded, decked, and shipped). All of their heads are in running Jeeps that are working well after several years of running from a Pismo Jeep to a DD to a Rubicon Jeep.

Edit: I have done the welded in bung on a set of Borla 17127's for use in a '84 CJ and an MPI...works well. I also did it on a set of these cheap headers (http://www.autopn.com/store/pc/viewprd.asp?idProduct=20009), which have been working well for about a year and maybe 10,000 miles in a '82 CJ7 with an MPI. Nice price and they seemed well made and are working well. Increased performance from stock like the Borla's as well...seem like a really high quality knock-off.

Sounds good... I have searched around and have yet to find a write up that mentions anything about welding a bung for the EGR tube... do you have and pics of this? Thanks

This is the only pic I could get...shows the O2 sensor welded into the set of 17127 Borla's (reference my EDIT above) in an '84 CJ with MPI and 4.0 head.

I am in the process of rebuilding the shortblock and installing a Clearwater 4.0 head on my 258. What cams have you guys had good luck with? I have looked at Clifford, Comp Cams and Crowler. Any sugestions? Thanks! T