Swapping in a 4.0 carb

[turbojn997]

Hello guys. Can ya'll help me with this? I've got a worn out AMC 258 i6 / 4.2l (blowing oil) Ive got a 4.0 fuel injected engine coming today for it. My plan was to swap in the 4.0 in place of my AMC 258 i6 / 4.2l , using my intake manifold/carb and distributor, 4.0 exhaust manifold. Is there any advice you all can give me with this swap to make it go easier? I've got a T-176 Transmission , weber carb, and gm distributor. I understand I'll have some minor fab work on my intake manifold and dent in the number 4 exhaust tube a little. Will the cam in the 4.0 work with this set-up? I would love any/all advice. Please pm me with anything ya'll have. I do not wish to go fuel injection because I love the simplicity of my carb set-up and don't want the additional costs of a wiring harness and pcm. Any thoughts on what kind of power I'll gain? The 4.0 is out of a 1997 Wrangler.

Thanks,
Jeff

 

[ThisGuyUKnow]

Hello guys. Can ya'll help me with this? I've got a worn out AMC 258 i6 / 4.2l (blowing oil) Ive got a 4.0 fuel injected engine coming today for it. My plan was to swap in the 4.0 in place of my AMC 258 i6 / 4.2l , using my intake manifold/carb and distributor, 4.0 exhaust manifold. Is there any advice you all can give me with this swap to make it go easier? I've got a T-176 Transmission , weber carb, and gm distributor. I understand I'll have some minor fab work on my intake manifold and dent in the number 4 exhaust tube a little. Will the cam in the 4.0 work with this set-up? I would love any/all advice. Please pm me with anything ya'll have. I do not wish to go fuel injection because I love the simplicity of my carb set-up and don't want the additional costs of a wiring harness and pcm. Any thoughts on what kind of power I'll gain? The 4.0 is out of a 1997 Wrangler.

Thanks,
Jeff

There is a dude in Colorado that modifies 4.0 Intakes to mount the carb.

 

[Dan77CJ7]

There is a dude in Colorado that modifies 4.0 Intakes to mount the carb.

Yeah i know him....lol when i picked up my MC2100, i met Gronk he mods and has a plate for the 98 "barrel intake" not for more HP but for a better volumetric efficiency. dude knows his stuff i wish i could explain what he had told me better. I lost the file he sent me about it, I'll email him, maybe it could be helpful?

 

[IOPort51]

just use the AMC 258 i6 / 4.2l intake that you have on the 4.0 head.

 

[turbojn997]

Thanks ya'll for the input. What do ya'll think about swapping around the pulley system. Do I swap my harmonic balancer? How about the water pump?

 

[ThisGuyUKnow]

Thanks ya'll for the input. What do ya'll think about swapping around the pulley system. Do I swap my harmonic balancer? How about the water pump?

If you got the full 4.0 I'd go completely serpentine but you may have to fab something for the ps pump of your keeping the AMC 258 i6 / 4.2l intake.

If you don't have the serp parts I'd suggest an early obd2 set up from a gc or yj as the tensioner is a better design.

All IMHO

 

[turbojn997]

Hello guys! I've been driving around for a month now after having done my AMC 258 i6 / 4.2l -4.0 High Output swap and thought I'd share how it went and what I've done. Everything, literally everything swapped right over form the AMC 258 i6 / 4.2l to the 4.0 except the pilot bushing. I bought a copper one for a AMC 258 i6 / 4.2l and had it machined down to fit in the 4.0. Other than that, smoothest thing ever. The intake sits on top of the alignment dowels, I swapped over the AMC 258 i6 / 4.2l water pump to keep my V-belt system. That gave me some trouble... The water pump impellers contacted the cylinder just a touch. I lightly ground them down, didn't have to take much off but it then fit great. Had to modify the power steering pump mount bracket because the intake now sits a little higher-easy fix, I installed a low pressure electric fuel pump to feed the fuel because I no longer had a block that would accept and mechanical fuel pump. The only other thing was the exhaust. I had to fab a new exhaust pipe-no big deal. After driving around for a week, I noticed that full throttle was not possible... It would cut out and bog down. I had a Weber 32/36 carb on the AMC 258 i6 / 4.2l that was swapped on to the 4.0. After countless adjustments it would never get to where it performed great. Either great at the low end and terrible at the high end or visa versa. I called Weber (who we have and account with) and talked with a tech. Turns out that the "economy" carb will never run that engine well enough. He explained that with the compression difference between the 2 engines, and a few more differences, it was at it's limit. He went on to say that the 38/38 Outlaw was really the only option with the setup I now had. Man... he was right. I bought the 38 threw it on and wow... Night and day difference. This engine swap, even with a carb on it, feels faster than a TJ with like tire size, lift, and gear ratio and I drive and work on those everyday.

Thanks to those that I have pm'd and responded to me with advice. You guys rock!

 

[ThisGuyUKnow]

Let me know when you want too inject that monster and really wake her up