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  #1  
Old 02-10-2008, 11:43 AM
Chucks1911 Chucks1911 is offline
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258 vs 360 swap

First I must admit that I am terminally inflicted with the Tim the Toolman disease (more power).

I did a search and most of the threads concerning this swap seem to be guys wanting to swap transmissions too. I dont care to do that.

What I have-a 77 J-10 with a 258, Th400, Qtrac with that extra drive unit (low drive? with the lever on the drivers side floor). This truck will be a street truck, seeing very little if any off road activity.

I just acquired a 78 J-10 with a 360 (less than 2500 miles on a rebuild), Th-400, and Qtrac. It is a complete donor vehicle. Reason that I'm not building this one is that the body is pretty much gone-RUST. I plan on rebuilding the Th400 and adding a shift kit while its out. I plan on adding the Summit 8600 cam, edelbrock performer intake, and probably the Holley truck avenger 670 carb to the 360.

Now I'm already aware of cooling system changes and exhaust changes. What I'm unsure of is the rest.
Can I basically pull the 258 and Th400 and just drop in the 360 and its Th400? Just removing these two items.
What about the "extra" part in my 77, the low drive(or whatever its called)? Is it worth keeping?
Will it be easier to swap the entire driveline(axles,trans,t-case, etc)?

I've seen in some of the posts that the 360 will need to be moved forward of the 258 mounting location? True? Can I just remove the 360 towers from the donor vehicle and weld/bolt them into the same location on my 77? Or should I just look for one that already has the combination that I want and buy it?

Is there anything else that I'm missing? Or anything else that I should be aware of? I will be doing the work myself. Although I haven't wrenched on any Jeeps, I have worked on/hot rodded Chevys for years.
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76 Honcho 360/T-18 4 Speed/Dana 20
77 J-10 with 258/TH-400/Quadra trac
78 J-10 with 360/TH-400/Quadra trac (for parts)

Last edited by Chucks1911 : 02-10-2008 at 11:47 AM.
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  #2  
Old 02-10-2008, 11:55 AM
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Gambler68 Gambler68 is offline
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Well..honestly I'd swap bodies, that'd be easiest since you have everything there.

Otherwise:

remove entire front clip

drop engine/tranny/tcase/and both driveshafts
from the I6 rig

(do the same for the v8 donor)

swap them, paying attention to using bolt holes from the v8 setup instead of the ones the I6 used. The inline 6 is a longer engine, so everything is moved back a few inches mountwise.

swap rad core section on the front clip and pass side inner fender (v8 rad is wider, and those rad support arms are welded onto the large inner front panel..it comes apart from the outer that the grill/lights attach to with about 400 1/2 inch bolts :P

You should be able to unplug the wire harness at the firewall and use the v8 one from the donor truck..

use the V8 linkages, your i6 ones will be wrong after swapping drivelines.

think that covers it?
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1979 Chero S "Sundog" 1979 Chero S "Hammer"
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  #3  
Old 02-10-2008, 12:20 PM
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tgreese tgreese is offline
 
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Knowing nothing more about it, I'd keep the entire BW1339 from the 258. You absolutely want to keep the low range, if not for you, then for the next owner of the truck. The 258 transfer case is probably in better shape, since you've been driving it and the 258 would cause less wear and tear than the 360. Put a new chain in the Quadratrac.

Also, if you aren't interested in the low range or 4WD, why a Jeep truck?

Should be a pretty easy swap, since you have the ideal donor already.
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Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination ATs, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
ECO Green: '15 FCA Jeep Cherokee KL Trailhawk
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  #4  
Old 02-10-2008, 06:19 PM
Chucks1911 Chucks1911 is offline
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A little bit more to try to clear some things up. The 78 donor vehicle was used as a farm truck. It is really more rusty (suspension, frame) than I'm comfortable with. It also has an old Arkansas title (actual owner had died)that will require some effort to convert to a good Oklahoma title.

Now for my 77. It has a fairly new spring lift kit with some nice 31 inch tires. The entire truck (suspension, frame) is in better shape. However, interior wise that isn't saying much. It needs a new radiator though. While the donor 78 has a good V8 radiator in it.

So would it be easier to just remove the front clips, disconnect the transfer cases from the transmissions, and then just install the 360 and its Th400 to the original transfer case in the 77? Or will this not work due to the difference in lengths between the 360 and the 258? Or will I just have to reposition the 360 towers in the same location as they were in the donor truck?

I forgot about the wiring. The fuse block on the donor 78 is basically toast. The PO kind of broke it up into various pieces, trying to "fix" it. I have a new 12 connection GM harness that I bought for another project some years ago that I ended up not using that is available for this.

I know, I'm rambling/brainstorming. Sorry about that.

Now as for why the Jeep and 4wd? I honestly can't explain. The truck just "speaks" to me. I don't really use the 4wd on my current daily driver an 06 Z71 crew cab pickup. It is my intention to finish the Jeep and turn it into my daily driver, selling the Z71, getting rid of that payment.
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76 Honcho 360/T-18 4 Speed/Dana 20
77 J-10 with 258/TH-400/Quadra trac
78 J-10 with 360/TH-400/Quadra trac (for parts)

Last edited by Chucks1911 : 02-10-2008 at 06:22 PM.
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  #5  
Old 02-11-2008, 01:03 AM
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Blue & Gray Blue & Gray is offline
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I didn't think there was a difference in the auto's length in regards to simply swapping out the engines and leaving the rest of driveline of the Driver Truck intact. Having two trucks factory equipped with the engines right in front of you would make this somewhat simple I would think. Everything from the Tourqe converter forward needs to come off the V8 truck, it's there and installed, reinstall on the Driver truck.



With both trucks intact you could simply look at the crossmembers and where the mount is landing on both. If the 6 rig lands the same as the 8 rig then why drop all that out? , if it landed inches back and could be shifted forward catching another set of holes or whatnot for the V8 application then you'd have some figuring to do. I'm curious as to what exactly you have to do here, I thought the Th400 Q/T was the exact same set up with the engine mounting position changing for whatever engine was installed. Hopefully someone will educate me on the exact differences and where they occur in the drivleine.
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1976 J10 258/T15/D20 , Dana44's w/4.09's 31x10.50 Super Swampers BP's. HEI an otherwise stock. Runs Great. SOA/SF and 2brl soon


1976 Cherokee NT 232/SM465/NP205, Dana44's, w/3.54. 35x12.50 Mud Chain Saws, SOA/SF, HEI. MSD, 2 brl, Wag seats etc. Hard Spanked but in work now.
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  #6  
Old 02-11-2008, 08:11 AM
Barney Barney is offline
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258

do you want to get rid of the 258?
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  #7  
Old 02-11-2008, 01:57 PM
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tgreese tgreese is offline
 
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Quote:
Originally Posted by Barney
do you want to get rid of the 258?

Barney, Oklahoma is a long way to go from Montana for a 258. Check your local 4x4 club and association boards, or even Craig's list ... 258s are common and inexpensive on the private-party used engine market.

(Sorry Chucks1911 )
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Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination ATs, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
ECO Green: '15 FCA Jeep Cherokee KL Trailhawk
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  #8  
Old 02-11-2008, 02:04 PM
Barney Barney is offline
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258 engine

Well thanks for the friendly advice...but...be advised I am headed to Texas thru the Oklahoma Panhandle within a month. If this gentleman was not to far from there it would not be out of my way. Where abouts in Oklahoma is he located please?
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  #9  
Old 02-11-2008, 02:05 PM
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tgreese tgreese is offline
 
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Quote:
Originally Posted by Blue & Gray
I didn't think there was a difference in the auto's length in regards to simply swapping out the engines and leaving the rest of driveline of the Driver Truck intact.
The engines are a different length, but that shouldn't matter for an automatic as long as you use the linkage parts from the V8. In the manual transmission trucks, the V8 has a spacer between the bell and the transmission so that the shifter comes up through the same hole with both engines - not an issue with an automatic. The crossmember will move though. I recall that you can't use the low range unit on a Wagoneer/Cherokee with a 258 and TH400 because the long drivetrain interferes with the fuel tank, but apparently that's not a problem in a J-truck.

Quote:
With both trucks intact you could simply look at the crossmembers and where the mount is landing on both.
Yeah, I'd say let the V8 truck inform the swap - compare everything before you take the two vehicles apart, and take lots of pictures and measurements for reference. Should be straightforward - hardest part will likely be taking the V8 frame towers off and welding them in.
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Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination ATs, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
ECO Green: '15 FCA Jeep Cherokee KL Trailhawk

Last edited by tgreese : 02-11-2008 at 02:08 PM.
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  #10  
Old 02-11-2008, 02:11 PM
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tgreese tgreese is offline
 
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Quote:
Originally Posted by Barney
Well thanks for the friendly advice...but...be advised I am headed to Texas thru the Oklahoma Panhandle within a month. If this gentleman was not to far from there it would not be out of my way. Where abouts in Oklahoma is he located please?

Well, that's a horse of a different color

(Sorry if i butted in).
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Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination ATs, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
ECO Green: '15 FCA Jeep Cherokee KL Trailhawk
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  #11  
Old 02-11-2008, 02:31 PM
Barney Barney is offline
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butting in...

I don't mind you butting in..I like your posts..I read them all the time. I just don't always tell everything I know. The last post on this forum I had I got beat up by several people. I knew what I was talking about and still do. Hopefully he will respond to my post, and if possible we might get together in a few. The only thing that keeps me from leaving for Texas now is the weather. I am escorting my wife down there in her Buick with my One Ton Dodge. I don't like her travelling by herself now, especially for long distances by herself. She will stay in Texas with her elderly Mother for all summer. I will go down to escort her back. It is a pain but I will not fly. You may email me a private one if you wish. Thanks for the post.
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  #12  
Old 02-11-2008, 07:35 PM
Chucks1911 Chucks1911 is offline
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Barney, I am outside of Lawton, OK.

Could it possibly be as easy as just pulling the 258, and dropping in the 360(of course swapping the V8 towers from the 360 truck too)? Meaning that I could leave the trans and T case in place?

Now to show my Jeep ignorance. I had guessed that the bellhousing bolt pattern on the Th-400 would be different between the 258 and the 360. Do they have the same bolt pattern?
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76 Honcho 360/T-18 4 Speed/Dana 20
77 J-10 with 258/TH-400/Quadra trac
78 J-10 with 360/TH-400/Quadra trac (for parts)
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  #13  
Old 02-11-2008, 07:48 PM
jinpdx jinpdx is offline
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The two engines share the same bolt pattern. The v8 will need to be moved forward, as well as the trans and tranfer. As I recall, the holes are already drilled in the frame for the mounts to bolt up. Unbolt the crossmember and move it forward to the next set of holes, same for the v8 towers. I'm not saying your truck is already drilled, but the one I did was.
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  #14  
Old 02-11-2008, 08:21 PM
Barney Barney is offline
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258/360 swap

1st Lawton is not that far out of my way. I have been told just now on the phone that you can swap engines. Take out the 258 and put in the 360, the bolt patterns are the same. However, I just read jinpdx's post. If he did it, he knows more about it than I do. I would listen to him concerning the movement of crossmember, etc. The man I talked to said you should not have to move anything, that out with the 258 and in with the 360 would work...IF they are both automatics, not one Manual and one auto. However, back to jinpdx's post. You cannot argue with someone who has done IT! I would listen to him but it does sound doable. Hope this helps. When you get a chance please send me a private message or and email, and tell me what you know about the 258 if you want to let it go? Such as: as it been overhauled before. Have you run it, and does it run ok or burn oil, etc. Does the engine code show that it is a 1977 258. Does it have an aluminum intake or the correct intake and exhaust which is cast iron. There is a big difference between the two. Does it have the Carter BBD 2 Barrel or does it have a 1 barrel? Just general stuff about the engine. Thanks
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Old 02-11-2008, 08:32 PM
Chucks1911 Chucks1911 is offline
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Talking

Quote:
Originally Posted by Barney
1st Lawton is not that far out of my way. I have been told just now on the phone that you can swap engines. Take out the 258 and put in the 360, the bolt patterns are the same. However, I just read jinpdx's post. If he did it, he knows more about it than I do. I would listen to him concerning the movement of crossmember, etc. The man I talked to said you should not have to move anything, that out with the 258 and in with the 360 would work...IF they are both automatics, not one Manual and one auto. However, back to jinpdx's post. You cannot argue with someone who has done IT! I would listen to him but it does sound doable. Hope this helps. When you get a chance please send me a private message or and email, and tell me what you know about the 258 if you want to let it go? Such as: as it been overhauled before. Have you run it, and does it run ok or burn oil, etc. Does the engine code show that it is a 1977 258. Does it have an aluminum intake or the correct intake and exhaust which is cast iron. There is a big difference between the two. Does it have the Carter BBD 2 Barrel or does it have a 1 barrel? Just general stuff about the engine. Thanks

Okay, no problem. As long as the weather allows me, I'll go out tomorrow after work and spend some time looking at the 258 a little harder for you. I will tell you right now that I bought it with a header on it.
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76 Honcho 360/T-18 4 Speed/Dana 20
77 J-10 with 258/TH-400/Quadra trac
78 J-10 with 360/TH-400/Quadra trac (for parts)

Last edited by Chucks1911 : 02-11-2008 at 08:35 PM.
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  #16  
Old 02-11-2008, 08:34 PM
Barney Barney is offline
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258/360 swap

Are you familiar with Novak Conversions? If not I suggest you do a google search on them, and read about the transmission/engines you have. They may be able to advise you also concerning your questions. Not to take anything away from the gentleman in the great state of Idaho but the more info you have maybe the better prepared you will be. Good Luck and I hope to hear from you..
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Old 02-11-2008, 10:55 PM
jinpdx jinpdx is offline
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The V8 needs to be moved forward for two reasons if I remember correctly.
1 to get it closer to the radiator to keep it cool
2 for the exhaust manifolds to clear the firewall.
It seems that there might have been another reason, maybe for the valve covers to clear the firewall, its been 5 or so years and a ton of other projects sense, so I don't remember everything. A friend and I did the conversion on his 75, or maybe it was a 76. Which ever, should be perty much the same as yours.
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Old 02-12-2008, 12:47 AM
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Gambler68 Gambler68 is offline
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uh yeah guys, pretty much what I said in post #2

forgot about the engine mounts, shouldn't have, took long enough to grind em off (its a half moon tab that's spot welded).
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1968 327 J3000 1978 J10SWB
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