I built my first 1200 hp, 93 octane engine about 8 or 9 years ago. I actually dynoed them on 91 octane, but never tried it in the boat. Always ran 93. After 2 seasons, we stepped them up to 1400 on 100 octane. They got freshened at 100-120 hours. I have since built quite a few pairs of them, the most recent in a 399 Skater V that I won the non-pro Top Gun award with at LOTO this year. They are actually made 1326 hp on the dyno, but I backed them down to 1229 hp in the boat. They have all been conventional head (no Big Chiefs) hydraulic roller engines. I am confident that 150 hours is possible. The longest I have taken one to is just over 125 hrs. and was very pleased with what I saw. I know there is more power to be had with Big Chiefs and a solid roller, but I would rather have the longevity and maintenance of the conventional heads and hydraulic roller. I'm sure there are a number of guys making over 1200 hp on pump gas. It really isn't that hard to do anymore.