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Discussion Starter #1
I have a 4.2L with a throttle carb injector from a chevy 4.3 swap. Well my motor started knocking and my passenger side motor mount bracket to block broke. Anyways, I bought a new block from a jeep grave yard thinking to just swap everything over. Problem is that i found out the block is 4.2L EF3235444 block casting number with a 4.0 head 0630 cast number on head. My question is what should i do? I dont know if i should take the head off my existing block thats knocking and put it on the new purchased motor and swap everything over being that I have all necessary parts or find a way to use the 4.0 head thats already on the purchase motor, but i wouldnt know where to start!? The head on the new 4.2l motor does not have the intake manifold. Your help would be greatly appreciated.
 

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Since you already have a throttle body conversion it would be simplest to swap the head so you can utilize what you have. The 4.0 head flows better and will make more power, but you will need intake and exhaust manifolds that will work with that head. Then of course you would have to figure out what to do for fuel delivery... rig up something to use what you have or go with a complete 4.0 MPFI set up.
 

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I have an 88 jeep wrangler that i converted to TBI. Full 4.2L motor and head. First time working on a jeep wrangler. Ran great. However the motor started knocking and the passenger side motor mount bolts to block casting broke. So motor is holding on one bolt there. So decided to buy another motor and come to find out the motor i bought is a 4.2L (3235444) block with a 4.0L (0630) head. Intake manifold or exhaust manifold was not on the new motor purchased. So its missing. Its just the 4.2 block and 4.0 head with power steering and alternator water pump with fan assembly on it. no wire harness.

My dilemma is what would be the easiest most cost efficient way for me to put this new motor together.

1) Stay with my TBI and swap everything over? If so how would i do that being that its a different head (4.0)?
a. Use the 4.2 intake manifold on a 4.0 head
b. or use a 4.0 intake manifold and get a TBI adapter plate to fit the TBI on a 4.0 head
2) Swap the head from my existing 4.2 thats blown over and do the same setup
3) Get the 4.0 MPI manifold and do a complete fuel injector setup from a later jeep model

Keep in mind im looking for the cheapest way to get it back and running. The 4.2 head might need to be rebuilt. Thanks so much forum
 
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