4.2 / 4.0 head swap - Hope somebody can set me straight!

[60biscayne]

Could someone expain this whole "God" thing to me?

Hay guys,
I've got a 1989 Wrangler with a 4.2, I want to get rid of the carb etc......
I heard of guys doing this modification & getting the benefits from the FI system & gaining a few horses in the process. I just want something that will start up without having to shoot starting fluid into it every morning to get it going! I've gone thru about 3 or 4 carbs & everyone stinks in one form or another.
We just got in a 2000 Jeep Cherokee with a 4.0 that spun a bearing. The customer is sending in another "Complete" motor - so the head & Fuel system is mine!
WHAT DO I NEED ETC., TO DO THIS SWAP?
I need another wiring harness & computer - Any particular year? Does it have to be out of a Wrangler - is a Cherokee OK - or it doesn't matter as long as it's a 4.0 set up..........
What about a fuel pump? What do I need to get to make this work!
Is there some type of modification that has to be done to either the head or the block?
Is there anything that gets plugged up etc.................
What am I missing?
If you want to email me, my address is jascush@localnet.com
Any help would be greatly appreciated.
Thanks,
Jim

 

[BigDaddys88YJ]

Try try this www.off-road.com/jeep/tech/4lswap/ hope it helps.

 

[Snitty]

if you have the 4.0 block, and have a 4.2... and want power... use the 4.2 crank and rods in the 4.0 block to make a 4.5 stroker

 

[Junkpile]

http://www.monsterslayer.com/jeep/40Head/40Head.htm


It's a great swap, and it opens all kinds of doors from a performance standpoint. Before going through with it though, why are you doing it? Is it for more power, or to just get FI? After the mods to the head and wiring and a new computer......will it be cheaper than just getting an aftermarket FI system to go on your current head?

The stroker is a very doable option at this point and would avoid the head modifications, but it comes back to what you want out of it as far as power goes and what you're willing to put in it as far as time and money goes.