When are you really going to push that thing? 500 hp isn't as large of a number as it once was if you peruse the diesel rags...
You can't push a non o-ringed, stock-rodded Dmax past 500 RWHP very far without breaking it. Many have tried. I am very happy with the HP output as is, but when it comes time to rebuild the engine, I'll beef it, maybe go with twins, add fuel, and she what she'll really do......... There are reports of 1000 HP on #2 out of a Dmax.
