4.2L to 4.0L swap

hey everyone. Was recently gifted a 1990 YJ. It’s in rough shape but it runs. According to the internet, Blue was not a factory color for the YJs in 1990 (title says 1990) but mines blue so I find that a little curious and the former owner says it’s never been painted. Not really too worried about the color but thought I’d throw that out there

My main question is has anyone swapped the 4.2 for a 4.0L? I have the AX15 manual 5 speed transmission. The current 4.2 has a ton of miles on it and I’ve found it harder to find parts for compared to the 4.0L. Can the 4.0L bolt right to the AX15 or is this conversion a pain in the ass?

I’ve been doing some reading on the Novak site, which is full of good info but I would like to hear from someone who’s done it. Thanks.

 

The conversion has been done many times, look on the net. The 4.0 in my opinion is the best engine that can be used for your application. Also mating up the AX15 is icing on the cake. Although do your research on that, A call to Advance Adapters in Paso Robles, Ca. should help you out:https://www.advanceadapters.com/

 

Thanks, I’ll check them out.