SWAP 4.2 FOR 4.0

[arktrans]

I have a 1985 AMC Eagle Ltd. . I may have to pull the head and do a valve job. I am wondering ,I just may do a 4.0 swap. Could I replace the whole engine. Would it mate up to the tranny and exhaust. What would the best 4.0 year to put int to the Eagle? Also in Ohio I do not need a emissions test as it is over 25 yrs. I would like to know how much of the vacuum and electronic stuff I could get rid of?.

[wagoneerhauler]

Hi.  There is a ton of info on this including a few write-ups.  Do a search and you will find a lot to read.

But to give a bit of a summary:
  Yes the 4.0 will bolt in as the axle mount boss is on the block.
  It will mate to the trans.
  The exahust needs a bit of work to fit around the axle hanger as you need the 4.0 exahust man.
  The "best" is said to be 92 to 95 HO.
  You will need decide on a carb or the 4.0 EFI.
 

[mudkicker715]

Eaglepedia item.

But why not go a step further and stroke it. If buying the 4.0 you already have. The necessary. 4.2 parts to stroke.

[amcinstaller]

x2 on MK. the search function is your buddy. here, eaglepedia, and google. lots of info elsewhere on the net for stroker advice too.

hint, look here

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[mudkicker715]

Sorry for the misplaced periods. My phone to me is goofy.

[arktrans]

Thanks for the info. If I decide to  do a valve job and keep the 4.2  I would also like to get rid of all the emission hoses and electronics that are not needed , because I do not need it in Ohio. Does any body have a step by step system to do this.

[thereverendbill]

i think i would do what tougeagle did to his 4.2  use a 4.0 head and upgrade that puppy to fuel injection

[shanebo]

I agree...Tougeagle has an awsome write up of his project...It includes an itemized list of parts and prices. Its a must see if your looking to do a swap.

[tougeagle]

Getting rid of all of the emissions stuff won't necessarily make your car run better. In fact, if your ecu is in good working order and all lines and switches are there, you'll make it run worse because the carb is extremely heavily dependent on vacuum feedback and signal from the various switches, the metering needles regulate air/fuel mixture at the main jets, and you'd need to go to a non feedback carb before removing everything. And, well, yes, EFI IS the best way to go... at least, if 0-60 in 8 seconds sounds like fun