78 cj5 258 I6 to Chevy 4.3 Conversion

[kidd79]

Guys.
I have just purchased my first jeep. It's a 78 CJ5 , with a very tired I6 AMC 258 i6 / 4.2l . From what i have been reading, it has a 3 speed Borg Warner T-150 . Everything works as of right now. I am very familiar with the chevy 4.3, and have seen a couple guys on several posts refer others to novak adapters. Thanks for that. Very good reading btw. My goal for this jeep is to have put in a 290HP 250 ft lb torque v6 in this thing. Strictly going to the local mud hole, and occasionally down to the sand pit near the house. NO ROCK CRAWLING or severe trail riding. Just want to load my daughter up and go get dirty in the mud hole.
So... I was wandering if anyone had done this before, what motor mounts, exhaust manifold's used, basically all the particulars. I am new to this btw if you couldn't tell. part#'s, pics, and all the free advice anyone is willing to give would be greatly appreciated.
Thanks in advance, and I look forward to getting to know you guys.
Cheers!
Greg

 

[81laredo]

I looked at doing this engine swap myself but decided against it. The Inline 6 came out on top after really looking at all of the costs and hassles. I was able to find the Bell Housing and Motor Mounts but the Wiring Harness and Exhaust were not available. Also the V-6 may break some of the drive-line components.
Take another look at the AMC 258 i6 / 4.2l but with one of the Fuel Injection kits. Mine has come alive with that and the HEI distributor, all parts to repair are readily available while traveling.

 

[kidd79]

Thanks 81laredo.
You wouldn't happen to have some links to some websites or anything would ya? I will definitely give it some serious thought. I would rather not go breaking stuff if i can avoid it. I forgot to put the rest of my goal list in my first post.
Mud riding, for sure..
up to but no more than a 4" lift, just enough to clear 31's and maybe later some 33's. I simply want the jeep to utilize all the potential that the driveline can support for moderate playing in the mud.
Thanks again.

 

[81laredo]

try this for adapters and mounts for the 4.3 swap;
The Chevrolet Small Block V6 Engine - Novak Conversions

but again do some research, the AMC 258 i6 / 4.2l is a good engine. The plastic valve cover has to go, I got my aluminum valve cover on ebay.
I am in California and have to deal with SMOG checks. I decided on the Howell EFI partially because of cost but also for simplicity and parts availability but the MOPAR EFI kit is another great choice just more $$$. If I was in another state I would have most likely stayed with a Carburetor or another EFI kit.
I chose the CRT HEI distributor and got it off of ebay. Be very careful and check the gear for hardness, thanks MN CJ7 ! check his posts for more information on timing and distributor setup.

I just drove the CJ7 for the first time after making the mods and I am very impressed so far. I made too many changes at the same time to tell you which one made the biggest difference but it is possibly the EFI. I put an Aluminum Valve Cover, Howell EFI, CRT HEI Distributor, Magnaflow Catalytic Converter and Magnapack Muffler. The AMC 258 i6 / 4.2l now has better power at lower RPMs, comes alive at mid-range and revs up past 4,000 RPM with better power overall.

 

[backbayJP]

My first post. I joined today. Thanks for the information. I am also considering the 4.3L swap but I may reconsider or at least keep an open mind about sticking with the AMC 258 i6 / 4.2l and convert to fuel injection. I can go either way because I already have obtained the 4wd 350 automatic and I also have the Tremac 176 manual Transmission . As already noted in another post there is information at Novak adapter on this swap. It won't be cheap.

 

[81laredo]

After doing allot of reading on this forum and another I decided that the AMC 258 i6 / 4.2l was right for me but that doesn't mean it is right for everyone. I think that the 4.3 is a great engine and I was interested in the swap but after doing some research I found out that the cost wasn't worth the return.
I would suggest that you start with a compression test, mine was at around 110 psi on all cylinders so the AMC 258 i6 / 4.2l was worth some up-grades. Basically I up-graded the AMC 258 i6 / 4.2l with Fuel Injection : Howell; Howell Engine Developments, Inc.
and HEI Distributor: CRT; CRT Performance, LLC
These are from 90's vintage 4.3L Chevy V-6 and really helped with my AMC 258 i6 / 4.2l L Engine after putting the Motorcraft junk in a pile on the floor of my shop.
Good luck on whatever you decide.

 

[kidd79]

Thanks for the info 81.
I am definitely going to check out the links and go from there on what i decide to go with.

Cheers!

 

[cooldaddy]

I, also am thinking of the 4.3 swap. not sure yet. however, if I do, then I will post all I can about it.

 

[81laredo]

I decided to go with the Howell Fuel Injection and the HEI Distributor. Really happy with how it turned out. The good and the bad is that I still have the old 6 Cylinder.
All in all I would do this again because it keeps the Jeep original for whatever that is worth. Look into the potential Axle issues with the V6 conversion.

 

[rr41mag]

What are you gonna do with your AMC 258 i6 / 4.2l ?