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2.8 to 4.3 swap

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I was wondering if anyone here has actually done this . My MJ is a 1986 w/AT 2.8. I am shopping around, have found some with a Vin W. But I would like to speak with someone who has actually done this conversion before I attempt it. I have had yars tell me that nothing will interchange . But the GM performance pages say it's possible. Cam someone e-mail me their phone number so I can directly speak to them. My e- mail is: rjhartman95@yahoo.com

Thanks to everyone

Bob Hartman

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A 3.4 swap is much more feasible. The 4.3, while being a V6, is a 90 degree V6 and uses the SBC bellhousing bolt pattern. A 3.4 is the same block as the 2.8, gives adequate power, and will bolt up the most of your original swap.


While it's possible to drop a 4.3 into an MJ with GM 4.3 stuff, it's just as much work as a 350, so you might as well do the 350.

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I don't see how the 4.3 could possibly work out better for cooling. It's a bigger engine ... both in displacement and physical size. It is, in fact, a small-block V8 with two cylinders lopped off. For the cost and work of the conversion you might as well do the V8.


The 3.4L GM V6 is the same 60-gegree block as the 2.8L and is a MUCH easier and more reasonable conversion.


[EDIT]Sorry -- disregard first sentence. Just re-read Dirty's post.

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For the cost and work of the conversion you might as well do the V8.



Maybe. The economics of the whole swap are goofy unless you have 'free parts'. If you had a desire for V8 power, then a V8 would be the swap to do and paying the extra price wouldn't be a big deal... If you wanted something milder, and had a bunch of stuff lying around, a 4.3 wouldn't be a bad idea. If you were in a situation where everything was junk anyways (all your 2.8 related stuff, trans, rad, etc etc) I'd recommend going to a 4.3 over a 3.4, even if the 3.4 would be more 'bolt in'. But, I'm more than willing to rip and tear as needed to make something fit.

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  • 2 weeks later...

The 2.8 and 3.4L are the same block externally (except for the fuel pump boss which is missing in the 3.4 and you'll need to get an electric pump). The only other big difference is the flywheels are balanced differently and you'll need to get your old flywheel neutrally balanced.


This page should help you out:

http://jeep.off-road.com/jeep/article/a ... ?id=277008

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