1979 4.2L 258 Upgrade options?
Posted: January 14th, 2021, 5:54 pm
Hi all, new to the site and I'm looking to modify!
I have a 1979 CJ5 with the 258, bone stock (with exception of a weber 38 carb i put on it ~15 yrs ago).
I live at 9500 ft elevation, and when I take it out sometimes go up to 12,000 ft, and can also take it down to moab at ~3500 ft elevation.
I am currently having problems with getting fuel on steep uphills (worn cam lobe?) and also tired of it running too rich and my wife hates the smell of unburnt (and non- cat) petrol.
Therefore, looking to modify it (I want to keep the 258 block - good compression on all cylinders, does not burn oil, etc.) and go with some sort of fuel injection.
So, I am curious about the 91+ YJ/XJ 4.0 head and EFI or other options (the Holly Sniper MFI?)
I've gone through a few old articles (~2007) of this swap and just wondering if this is still a good option, or if anything new is out there.
The Mopar kit seems pricey, and the only one I can find is for 1981 and newer.
A couple of years ago with this on a wish list in my mind, I did buy a rebuilt head 0630 casting, wiring harness and ECU for like $150 - low enough that if the better option is to start fresh, i'm ok with that.
Any thoughts and suggestions?
Anyone in Colorado that has experience with this?
Cheers!
I have a 1979 CJ5 with the 258, bone stock (with exception of a weber 38 carb i put on it ~15 yrs ago).
I live at 9500 ft elevation, and when I take it out sometimes go up to 12,000 ft, and can also take it down to moab at ~3500 ft elevation.
I am currently having problems with getting fuel on steep uphills (worn cam lobe?) and also tired of it running too rich and my wife hates the smell of unburnt (and non- cat) petrol.
Therefore, looking to modify it (I want to keep the 258 block - good compression on all cylinders, does not burn oil, etc.) and go with some sort of fuel injection.
So, I am curious about the 91+ YJ/XJ 4.0 head and EFI or other options (the Holly Sniper MFI?)
I've gone through a few old articles (~2007) of this swap and just wondering if this is still a good option, or if anything new is out there.
The Mopar kit seems pricey, and the only one I can find is for 1981 and newer.
A couple of years ago with this on a wish list in my mind, I did buy a rebuilt head 0630 casting, wiring harness and ECU for like $150 - low enough that if the better option is to start fresh, i'm ok with that.
Any thoughts and suggestions?
Anyone in Colorado that has experience with this?
Cheers!