I've purchased and/or tried those other computer engine building/dyno products and never found what I was looking for. It all started about a year ago when I was looking for one of the products to estimate piston to valve clearance and I would have paid good money for it, but none were found. They didn't even ask for the information needed to determine it. Sometimes if you can't find what you are looking for, you just have to build it yourself, so I did. Of course being an ASE certified engine repair mechanic to get myself through school for my aerospace engineering degree helped, along with building several of my own engines over the years. I've used my program to build my most recent engine, and after checking with clay, found it was accurate to a few thousandths in intake and exhaust piston to valve clearances, and within 10% of chassis dyno rear wheel torque and horsepower. I actually found a problem with my cool air intake restricting air flow after I put it on the chassis dyno and it was reading less than what the program had estimated. So I am very happy with it, and I'm sure others will feel the same.
