I had a Smith Bros 3/8 .083 wall heat treated pushrod break in two pieces during a dyno test at 5600 RPM, it knock the top of the roller lifter off, bent the pushrod beside it and ended up dropping into the lifter bore gauging it and the cam lobe I had Smith Bros custom make them, told them all about the motor specs, spring pressures, intended RPM and so on I help some other local racers that own a dyno, they had one of there Smith Bros pushrod break the top off of one during a dyno test also I replace my Smith Bros with a set of seies 3 Manton .120 wall that Terry Manton recommended and that motor made 8 more HP at 300 RPM higher during the next dyno test, A,B,A after fixing the motor Smith Bros did replace the two bad ones free but didn't offer any other help on replacing or fixing the bushing, lifters and camshaft ( I didn't ask them to either )