I HAVE AN 01 450 ES THAT HAS PRETTY MUCH ALL YOU CAN DO TO IT.HERE IN WESTERN CANADA OUR ALTITUDE IS AROUND 2500 FEET ABOVE SEA LEVEL.THE STOCK 8:5 COMPRESSION MAKES OK POWER UNTIL YOU BOLT ON 27" TIRES.I DECIDED TO BUY HIGH LIFTERS 10:25 PISTON 0.020" OVERSIZE.I PORTED THE HEAD AT THE SAME TIME.FOR THE FIRST BREAK-IN TANK OF FUEL I MIXED PREMUIM GAS WITH VP RACING FUEL C-12 AT 50/50.THE ENGINE RUNS REALLY STRONG,SOUNDS EXCELLENT, BUT SEEMS TO RUN HOT.ANYONE OUT THERE HAVE ANY SIMILAR EXPERIENCE WITH THE HIGH LIFTER PISTON ???