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Unread 11-13-2012, 08:33 PM   #1
danm3275
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Another 4.0 head swap conversion and questions

So my headgasket went south on my 4.2 258 and i decided to do the 4.0 swap.
I got a clearwater head, borla style 4.0 exhaust, gaskets, and an aluminum 4.2 intake.
I take it all to my mechanic who specializes in carbs ( I dont have the tools needed to do the job, apart from not being able to lift the head due to an injury)
Luckily it's in a Scout II so clearance issues with the powersteering bracket dont apply ( It's like a living room in there)
This is where it gets fun.
The borla headers rub against the intake mani so he was stumped.
The intake sits above the dowels ( he was stumped again)
The holding of everything together with spacers seemed dangerous to him also.
I told him about the header adjusting, and the washers ( still seemed stumped)
Whats a good solution to the washer issue, and how should I go about having the headers modified?
Even better, anyone in the LA Area know how to do this and can help for a six pack and lunch? ( not actually do it, just advice and guidance)
Or a shop that can knock it out easily?

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Unread 11-13-2012, 09:17 PM   #2
jeepwhore
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What head casting is it? Possibly have a mismatched header/intake for the head being used?
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'84 CJ-7: Yota axles (spartan locked front, e-locked rear) 4" BDS, 1" Daystar & 3/8" shackle lifts, 35" X-Terrains on steelies, YJ Tub & family roll bar, heater blower upgrade, 4.2L w/MC2100 & Team Rush, Warn 8274. Rebuilt 4.2/4.0 hybrid, AX15 and twin sticks/clocking ring waiting to go in.

The advertised position for a topless, dirty jeep girl has been filled......by my wife. Thanks to all that applied.
<------------and yes, that is her.
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Unread 11-13-2012, 09:50 PM   #3
danm3275
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It's an 0630 and should work with the 4.0 headers and the 4.2 intake from what I've read
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Unread 11-13-2012, 10:03 PM   #4
jeepwhore
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Ah, I missed the part about the 4.2L intake.

There is some modification of the 4.2L intake required to fit with the 4L header. Either relocating the dowels or notching the intake.....I recall reading mention of them both.

Check out this photo abum....there are pictures of the problem and how to remedy it by slightly grinding the intake:

http://picasaweb.google.com/85YellowCJ7/40HeadSwap#

The pictures show a stock 4L exhaust header so I'm not sure how different the flange of your Borla is.....it may require more grinding of the intake than shown.
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'84 CJ-7: Yota axles (spartan locked front, e-locked rear) 4" BDS, 1" Daystar & 3/8" shackle lifts, 35" X-Terrains on steelies, YJ Tub & family roll bar, heater blower upgrade, 4.2L w/MC2100 & Team Rush, Warn 8274. Rebuilt 4.2/4.0 hybrid, AX15 and twin sticks/clocking ring waiting to go in.

The advertised position for a topless, dirty jeep girl has been filled......by my wife. Thanks to all that applied.
<------------and yes, that is her.
:-D
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Unread 11-14-2012, 03:48 AM   #5
gmakra
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The easiest way is to remove the dowels or enlongate the holes on the manifold and then get big washers to bridge in between the two manifolds. There are two reasons for this one is the flange thickness is different between the two and you have to slide the intake manifold around to get it to cover the gasket. There is not much realestate so what I have done is place the gasket over the intake and when you get the most amount of sealing surface trace the outline on the intake manifold side. This way when you put it together you can see where it should go.
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Unread 11-15-2012, 08:08 PM   #6
danm3275
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Thanks for that! I have the intake and exhaust squared away, but now because it's a 74, the rockers dont fit ( I found out that from 79 and up they all work, but pre 79 they were different)
I got new rockers and pushrods for a 4.0 head and hopefully that will get me back on the road!
Apart from that, anything else i might look out for?
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