Cast vs Billet | MounTune Motorsport Engine Block Design [TECH TALK] What considerations go into taking a 150HP engine and making it produce 600HP with huge cylinder pressures, reliably? When you want to double, triple or even octuple an engines output, at some stage you’re going to find the limitations of your factory block and head castings either in dramatic fashion or via constant repairs and rebuilds for ‘minor’ issues. In professional motorsport, either outcome is unacceptable. David Mount