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Old 03-03-2015, 08:04 PM
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kyamcalvert kyamcalvert is offline
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4.0 head swap on mild 258 build questions

I recently bought a built 258. It was a race motor in a Javelin. .046 over with Chevy 305 hypereutectic pistons, custom cylinder head with BBC roller rocker setup (ridiculous compression ratio with that stuff), and a used 4.0 head with it to make it suitable for pump gas.

So, what's everyones experience with the head swap? What should I do about the water jacket issue? JB weld and quiksteel reeeeally sketches me out. Should I spend some dough on the 4.0 head since it's going on such a nice motor? Any and all advice is appreciated.

Also, if anyone is running a Weber 38, any words on that would be cool. I run a 32/36 on my other 258 and LOVE it. This one will be geared toward a peppy daily driver with less of a concern toward economy.
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1982 Wagoneer Brougham
258/T176/219/Weber 32/36
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Old 03-03-2015, 11:22 PM
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rockosocko rockosocko is offline
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never heard of using the 4.0 head.. Hhmmm.

You got links to this?

E
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  #3  
Old 03-03-2015, 11:38 PM
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kyamcalvert kyamcalvert is offline
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Google "4.0 head swap".
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1982 Wagoneer Brougham
258/T176/219/Weber 32/36
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  #4  
Old 03-04-2015, 06:31 AM
mokurt mokurt is offline
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I saw an ad in a recent 4-Wheeler mag. for a new bolt on 4.0 head that will fit the old block.
Edelbrock ?

I know there are write ups on the web,try searching.
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Last edited by mokurt : 03-04-2015 at 06:42 AM.
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Old 03-04-2015, 06:32 AM
mokurt mokurt is offline
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this site is messed up this morning!
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  #6  
Old 03-04-2015, 08:00 AM
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rockosocko rockosocko is offline
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Yep, Found it after i replied last night..

Interesting to say the least.
If one wanted to, they could use a tig welder and fill the holes with bronze/brazing rod or the like. It would take some time and might get a little frustrating, have to get it decked, but at least it would be "METAL" filler. OR, one could try and drill out the little tri-angle water holes to a circle and tap in a brass plug, THEN deck it.

I'd like to see a 'built' 258 with a 'filled' Edelbrock 4.0 head tested and THEN compare to a 4.0 stroker w/E-brock head and see how similar/different the torque/HP values would come out..
In other words, if it would REALLY benefit someone to build a stroker VS just pop a later model head/FI on a 258 and be done..

E
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  #7  
Old 03-04-2015, 08:57 AM
SJTD SJTD is offline
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I wasn't about to trust something that critical to glue either.

I tried the TIG braze. Didn't work for me but prolly due to my skill level not the material/equipment.

Weld shop instructor I knew recommended getting 99% nickle fluxed rod and knocking most of the flux off and using that with the TIG. Worked ok but I had trouble with it building up as I got to the center of the holes so when ground back down it was too thin.

Kept at it, had it decked with specific instructions that I didn't care if the welds cleaned up since they aren't in an area that has to seal. Just take enough to assure the thing was flat. Now have about 20k on it.

I've read that some blocks are wide enough to cover the holes?

I used a magnetic mount drill to drill/tap the holes for 1/2" bolts.
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  #8  
Old 03-04-2015, 09:23 AM
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j2sax j2sax is offline
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HardBlok

http://www.hardblok.com/product-info/

There are numerous writeups on filling the waterjackets/head gasket swaps, etc... lots of guy on the "Eagles Den" website have done this. Hardblok is normally the choice for many reasons.

There are Drag race motors making THOUSANDS of horsepower that use HardBlok... trust me it will work in your head and there is no chance of warping it from heat.

If I were making a hot daily driver I would use the EFI from the 4.0 (91-95) with a 99 intake (probably have to go Hydroboost or a more narrow booster. You can research the "5 wires to fire" and go to "theamclist" website and you will find several guys who have gone this route.

THEN there are ALL KINDS of articles on spicing up the 4.0 using larger injectors from Mustangs and others.

You can use many different styles of headers from Factory to Borla.... large single or dual exhaust.

Probably more than you wanted, but you did say any and all advice! Look forward to seeing it run!
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  #9  
Old 03-04-2015, 11:47 AM
SJTD SJTD is offline
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Never heard of the stuff. The picher shows the water jacket in a block 3/4 full?

Seems a different application than in the 4.0 head where you are filling some holes that have to be leak free rather than filling a volume.

Cement based with metal filler. How does it adhere to the head for leak free interface?
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  #10  
Old 03-05-2015, 03:36 PM
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DieselSJ DieselSJ is offline
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One of the best solutions I saw was to use a mill and make all of the water jacket holes circular and install freeze plugs
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  #11  
Old 03-08-2015, 07:38 PM
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cu4whln cu4whln is offline
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I did this swap when I built my CJ 258. Original stock set up, with full emissions would barley do 70 max. after the swap? It will go 100.. with 4.10s and 33" tires. NOT that I want to go that fast on my CJ !! Way better low end power, no issues off camber any more. Always runs great in all conditions.

Anyway, we brazed up the offending water passages... BUT - we heated the head up to 400 degrees first to prevent warping. Then, took the head in for a full valve job and recondition - also had the head surfaced to ensure flatness.

BE SURE TO USE A 4.0 L HEAD GASKET ! Don't ask "why" I know this

I also swapped in a 4.0L stock cam, lifters and pushrods. [ Make sure to use EITHER 258 lifters and pushrods, OR use all 4.0L stuff - they are different heights.. total stack is the same, but use matched parts. I put a 4.0 L cam in since I was making it fuel injection at the same time.. figured the factory cam matched the engine computer, right?

I made my own fuel injection btw - the Mopar kit is based on a 95 YJ wire harness... I printed the directions and wiring diagrams. Turns out it all matches right down to the colors. Used a factory YJ manual to put it all together.. with some frustration I might add! Just had to find a 95 YJ and pulled ALL the under hood wiring.. all the way back to the tank... its all there.

Have fun.
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1977 "401" 'Da Chief
1979 Chero: "Madness" [Sold]
1985 CJ : Renegade -locked and loaded
2001 XJ : Driver 2016 JK 2 door

'Da Chief here: http://www.ifsja.org/forums/vb/showt...ighlight=chief

Round 2- LT Swap: 'Da Chief:
http://www.ifsja.org/forums/vb/showthread.php?t=188457

"Madness" build here:
http://www.ifsja.org/forums/vb/showthread.php?t=89280
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  #12  
Old 03-09-2015, 08:18 AM
SJTD SJTD is offline
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What did you use to do the brazing, TIG or gas?
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  #13  
Old 03-09-2015, 01:04 PM
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cu4whln cu4whln is offline
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Quote:
Originally Posted by SJTD
What did you use to do the brazing, TIG or gas?

Gas I think. My buddy is an expert welder - this was 16 years ago....
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It's not yours 'til ya bleed on it . . .

1977 "401" 'Da Chief
1979 Chero: "Madness" [Sold]
1985 CJ : Renegade -locked and loaded
2001 XJ : Driver 2016 JK 2 door

'Da Chief here: http://www.ifsja.org/forums/vb/showt...ighlight=chief

Round 2- LT Swap: 'Da Chief:
http://www.ifsja.org/forums/vb/showthread.php?t=188457

"Madness" build here:
http://www.ifsja.org/forums/vb/showthread.php?t=89280
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  #14  
Old 03-10-2015, 08:53 AM
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kyamcalvert kyamcalvert is offline
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Just talked to the owner of a reputable machine shop. While the shop may be reputable, he is clearly not a fan of AMC.

Dirty secret: this motor is going in an Eagle.

He basically told me to shove it. Said he wouldn't plug the passages "cuz it'd cost you more than the whole head is worth", "no one likes Eagles anyway", and that I should "sell the motor to a CJ guy and rebuild" what I've got.

When I mentioned FSJ's over CJ's he just laughed and said he had to let me go...after all, he has work to do...

Gotta love the AMC thing...
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258/T176/219/Weber 32/36
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  #15  
Old 03-11-2015, 10:10 PM
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j2sax j2sax is offline
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Hardblock will do a great job at a fraction of the price and the Eagles Den (formerly "Nest) has had several who have tried it. It is also a staple of drag racers everywhere.
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