I had a set of custom made Smith Bros. 3/8 pushrods that were supposed to be .120 wall 3/8 diameter, one of them broke in my test mule motor on the local Studka engine dyno at 5200 RPM. That pushrod broke into two pieces (it had a metal flaw in it where it boke) and bent the one next to it and falling out allowing that pair of roller lifters to pop out of the lifter bores allowing the broken one to get into the bore and gauge the cam lobe
When I took those two bad ones back to them they told me that those pushrods were .083 wall, not the .120 wall I had ordered and paid for They replace the two broken ones for no charge.
I ordered a set of identical Manton .120 wall x 3/8 diameter and made five more pulls on the dyno with the Smith Bros. pushrods and them swap in the Manton's with no other changes and they made 8 HP more at peak RPM (6700 or maybe 6800 RPM, CRS now , they gained more power from the start to the finish of all pulls after that
My last Hi Po bracket motor had Manton7/16x.145 wall pushrods on the exhaust valves and 3/8 to 7/16 single tapered pushrods on the intake valves to help add some more clearances on them to the head up high near the valve cover gasket surface