I know Jason A has discussed this before but just wanted to revisit it. The Montero SOHC 3.0 V6 sits at approx 150 HP while the Diamate 3.0 SOHC output is 175 HP. How is this extra 25 HP achieved exactly?

The reason I'm curious is my wife's 89's engine was replaced by some previous owner with what appears to be a diamante engine. I've came to this conclusion due to the valve cover configuration(matches diamante in 6G72 rebuild manual) as well as the timming belt cover (which I've since resored to the Montero correct cover). The Timing sprockets are cast not stamped so I know its not a crysler mini van variant. from looking at the rebuild manual there's an supposed to be an H code on the cams of the Diamante and a G on the Montero Cams. I guess I should of looked for that when I changed the Valve cover gaskets <img src="/forums/images/graemlins/lol.gif" alt="" /> The Distibuter, intake and exhaust are Montero correct of course and the engine runs very well and seems curiously peppy. Should I be running premium gas in this engine if its diamante? Change in timming? I guess this requires further investigation on my part.