Had the privilege to restore Billy Canfields 1969 Police Special, ground up, wheel to wheel. What a beautiful motorcycle. It took a couple years to build, working on and off. But the end of the build yielded some trouble. I used a Andrews A2 grind with low compression pistons and the heads had all new parts including seats. I always grind new seats to leave as much stem height as I can with the cam Im using, in this case, basically stock, Andrews says the A2 can be used with stock spring spacing and Hydraulic lifters, a "bolt in" cam. Well after almost 30 years of building engines, i'm still learning. I had broken inner valve springs, on two separate accessions, so I had the upper end off of this Shovel three times! With the help of Steve Broyles at Stevenson Cycle, we put our heads together and found some old Shifton spec's and discovered there is a in pocket measurement between the valves heads and a little math that includes the lift and walah! I had to change the spring spacing and sink the valves deeper in the heads! Hey Andrews, its not a "bolt in" camshaft! You can do the exact same thing to two separate engines and the end result is, they are two separate engines. No two are the same, they have there own personality and character. After all said and done, a great bike, a great experience and i'm sure its ready to ride!