Amc258 4 Barrel Worth It?

No, I used a GM TBI and a Megasquirt EFI computer on the 258 intake to convert it.

 

So a lot of us know and love the 2G.. simple, reliable and who knew.. A race carb.. that could be adapted!

https://www.motortrend.com/how-to/ctrp-1101-rochester-2g-carburetors/

 

I am following this thread with a lot of interest. My current project is a 74 CJ5 with the original 258, a Clifford intake manifold, a Holley 4-barrel carburetor, and a Headman header. The engine is tired, and my gut feeling is that it has never been rebuilt. So planning my next move, I would like to freshen up the engine with a simpler intake and exhaust system. Dependability and fuel economy are high on my list. I want to use this rig for cruising the backcountry around my place, and I want to stick with the 15-gallon tank!

In 2017 I purchased a new 450 KTM dirt bike first year with EFI. I cursed it the first few months till I got the software sorted out. A carburetor was looking really good. After sorting it out, it has been super dependable. It has been upside down many times, and I have put thousands of miles on it in very rough terrain with no issues. The big selling point is that it runs perfectly hot or cold with about a 35% increase in fuel economy with better power and throttle response than the same motor running a carburetor.

So with all that, I am looking at EFI for my Jeep. The Holly Snipper system with an electronic ignition has my interest. Megasquirt looks good but may take more effort than I want to put out. I think maybe just using a 4.0 cast iron exhaust manifold or a JBA SS shorty header. I see a few have been using Crysler 4.0 stuff pulled off wrecking yard doners.

So short story, keep posting so we all can learn something here!

 

There is a lot of good first hand information in this. Had a 289 Mustang that was mildly warmed running a Holley 780 single pump with mechanical secondaries from a 67 Fairlane 390.
Never did a thing to it than dump it carburetor cleaner and hose it out as needed at times.
Ate lots of Chevys. The carburetor charts would say it was way too much but the little motor couldn't
read. Got 20 miles to the gallon on the highway. I have kept the receipts on this car for 50 years. Don't know why...

 

I have the 4.2 in my 89YJ and I put a small Rv cam and hei distributor and a MC2100 with a two inch adapter I found online. The MC2100 was used on small ford v8’s in the late 60 and 70’s. It has a lot of torque and I get about 12mpg on highway.
If I every upgrade the motor I am going with a 4.7 Stroker from Titan in OCALA Fl.