1986 2.8 v6 to 4.0 swap info?

I have been told that the '84-'87 xj's have a smaller front end. Is this true? Will I have room for a 4.0 or 4.3 swap? Thanks

You need to do some hammer work on the firewall to get a 4.0 to fit, I'd go the 4.3 route myself. Thats more or less a drop in.

the 4.3 will even take some work. The best swap for you will be the GM 3400 or 3800 series v6 motors. They are close to a direct swap. Then you can scavenge a Buick or chevy supercharger from one of the 3400 series motors and it is a bolt on.

wolfpackjeeper said:

the 4.3 will even take some work. The best swap for you will be the GM 3400 or 3800 series v6 motors. They are close to a direct swap. Then you can scavenge a Buick or chevy supercharger from one of the 3400 series motors and it is a bolt on.

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Wait a minute, I thought the 2.8 and 4.3 were the same block. Or is it the 3.4, I have not kept up on it, yea I guess it's the 3.4 direct replacement.

RichP said:

Wait a minute, I thought the 2.8 and 4.3 were the same block. Or is it the 3.4, I have not kept up on it, yea I guess it's the 3.4 direct replacement.

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I know the 3.4 is the same block, it was my understanding that it is similar to the 305/350/383 difference.

I am reasonable sure a RWD 3.8 from a camaro will bolt up as well. I am unsure if the 4.3 will work easily, I think it is one of the swaps where a v8 starts becoming more practical.

2.8/3.1/3.4L are all 60-degree V6 engines, and will swap readily. Easiest way to make sure you have a RWD-capable version (FWD puts the starter motor on the wrong side) is to get one from an F-body (Camaro/Firebird) or an S-series. If you can find an S-series donor with an entire powertrain 1988-up, go ahead and get the whole powertrain. That will also net you the overdrive gear availaable in the THM700R4/4L60 (later versions are electronically controlled 4L60E - do not want. 1987-earlier THM700R4 have a massive flaw in the valve body - do not want.)

The 4.3L is derived from the Small Block Chevvy, and should go into SBC mounts. Find that one in later S-series, some K5, some K10, and Astro/Safari.

While looking, don't neglect the FWD as possible donors. Slide under and look for a starter motor mounting pad on the rear side of the engine (as mounted.) This indicates a Goodwrench Service Replacement block, which was cast and machined with starter motor mounting pads on both sides of the block to be used in FWD/RWD applications. You simply use the other starter motor mounting pad.

If you get an FI donor, grab the wiring harness and electronics package as well. The FI systems used on them are actually quite efficient, and I understand that the GM FI systems are highly tunable with minimal equipment.

shoot, you can tune a GM car with a damn PDA nowadays

wolfpackjeeper said:

shoot, you can tune a GM car with a damn PDA nowadays

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Exactly. That's why I've long wanted to see about adapting GM V6 DIS to the 4.0L - should make supercharging, forced induction, and exotic fuels that much easier to try out!

It has always amazed me how Chrysler encoded their ecm's such as to make tuning nearly impossible. And it is not like they sell a product to fill that niche either. GM's and to an extent Fords are very open to programming. And they license the programming systems out to other companies, LS1Edit, GMTune, ect. It is as hard to tune a Jeep as it is to tune an import.