Your source for custom machined products for the stock or bored and stroked Jeep Inline Six for ten years now.

 Turn your 4.0L into a stump pulling 4.6L!

Prior to the introduction of the Jeep 4.0L in the Cherokee back in the late 80's, AMC owned Jeep and equipped the CJ and YJ with the venerable 258ci straight six. That came to an end with Chrysler's acquisition of AMC and subsequent phasing out the the 258 with the 1990 YJ.

The 258 was a good offroad engine, owing it's great low-end torque to the generous 3.895 inch stroke of it's crankshaft. All was not well in Jeepdom though, the performance of the 258 suffered greatly due to a crappy carburetor, poor head design, small bores and tons of emissions junk.

With the 258 phased out in '90, Chrysler's engineers reworked the fuel injection and head design of the 4.0L Renix, which had already been serving the Cherokee well,  and gave it the title H.O. in 1991. What the 4.0L H.O. brought to the table was a better head, better fuel injection and a much bigger bore. 3.875in as opposed the 258's 3.75in bore, but with a much shorter stroke of 3.44in. The 4.0L/YJ XJ has turned out to be an awesome combo and sadly, history as of the 2006 model year. But, with it's small stroke it was basically more of a street engine when compared to it's predecessor. Most Jeepers I have met swear by their reliable six and, why not? Let's face it, there aren't many engines that can go over 200,000 miles and still keep going.

With that in mind, to have the best of both worlds, Jeepers started putting the the 258's crank and shorter rods in the 4.0l's block, with it's bigger bores. Viola, 240 HP plus-perfection!

Enough of that. If you found your way here then you are already looking to start or finish a Jeep build. I will have more technical info sooner or later but there is never enough time to work on the site.

 Through hard work and determination I have built a well deserved reputation for quality work. I roll on the same parts I sell. Fourteen years now in the same '93YJ which started life as a four banger, went to a stock 4.0L and now the 4.6L stroker.

The finest 63mm bored throttle body available, powder coated.

Max airflow with an extra millimeter to port match to your intake.
One of the very few places to find custom dished pistons. Silvolite 2229's with a dish sizes from 18cc's and up.

For use with a 4.0l block, long stroke 4.2L/258ci crank and