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I will point out that both of the motors you have located are OBD II which creates even more differences in what they have on them compared to what you have. OBD II began in 1996.

Dons suggestion of doing the full XJ swap is not a bad idea but IIRC the gauges on the OBD II XJ went to can bus comms to the cluster from the ECM. I am positive that the TJ in 97 was that way and have no reason to believe the XJ was any different.

There is no clear cut answer IMO and things little things like a cable or some wiring can create some serious roadblocks for some people. The actual swap may not be that bad, but the details may kick your butt.

There is no way for us to know your mechanical aptitude, what tools and shop equipment that you have, etc. Because you asked the question though it comes across as it may not be as easy for you as it is for others. There are a lot of variables. Yes. Swapping a SBC for another sized SBC or even going SBC to BBC was simple. It really is not a simple and straight forward as that in todays world.

There is no way for us to know how long it will take you. I can do things in an hour or two that take others a weekend, a week, even a month or a year because I do it everyday and have scads of tools and equipment and other resources at my disposal. You can put 10 experienced guys in one shop with the exact same resources and the speed that they will accomplish the same thing can vary greatly.

I am not by any means trying to discourage you but the fact that you posed the question along with the fact that you say it is confusing would make me think that you are going to go through a lot more 12 packs than you anticipate to get it done.
 

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Everybody who has suggested a 4.2 long block is really suggesting the easiet way to success. I will even add having a local reputable machine shop do a rebuild for you if you can verify from a good source that the machine shop is good, or you or somebody you know is knowledgeable enough to know if the machine work they did is up to par and do the rebuild yourself. I personally have not run into all these terrible machine shops that are supposedly out there in the world but have the blessing of dealing with many through work and get to see their work and its quality before I ever send them something of mine. LOL.

The Holley Sniper does have a BBD replacement system. It looks great on paper, I would love to lay hands on one. I believe that it most likely works well. The Howell system is proven. Many forum members swear by it. This has all been said but just re-emphasizing some good info.

Another place you can look at for EFI is affordable EFI. Some of their stuff is similar to the Howell because it is based off of the GM TBI systems.

Nothing wrong with sticking with the carb and it would be easy if you stick with the 4.2. Just pointing out that there are other options which may be easier than a 4.0 swap and a big reason people like that swap is they gain fuel injection.
 

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This is my 2 best guesses it jumped timing or intake gasket. I pulled the distributor cap and rotated the engine with a wrench and went to 0 on the timing mark, now I rotated it once to 0 and then one more around to 0 and checked the closed the rotor pointed to was #3 cyl. What do you guys think?
Thanks
You are on the correct path. The firing order is 1-5-3-6-2-4 on the 4.2. So at TDC with your timing mark lined up to zero your rotor should point to #1 or to #6. There are two crank revolutions to one cam and distributor revolution so it will be at #1 on one revolution and #6 on the next revolution or vice versa.

The causes of what you have are a bad timing chain or gears which can include broken keyways or dowels that locate them to the component. The other is an apple cored cam and distributor gear or a broken distributor roll pin.

If it ran good and was quiet, you probably have an engine that is very repairable.
 

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If it is out of time due to the timing chain being off, it will not have normal compression readings. They usually have low readings across the board but there can be a cylinder or two that has unusually high or normal readings. This is because things are not moving in the proper sequence. (pistons and valves)
 

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Thanks for posting back. Glad to hear that the community was able to help. We love success.

Where are you located? That is close to the temps we are having.
 
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