looking for those 150 heads. What's your fuel recomendation Barry? 92 should be ok don't you think. Keep in mind I still run the stock oil injection pump. 150 heads with the comp gasket won't put my volume under 35cc will it? The 200 two piece heads are cut to 35cc. Centurions aren't the fastest hull on the water so ultra high speed is not the primary goal. I run a 21 inch High Five Merc 5 blade prop at 6200rpm. This yields about 60-65 mph on the twin 80mph Airguides. I have a CMC jack plate with your basic setback (5-6in.)and a max lift of about 6". It's fun but it aint no Allison!!!!