I know the feeling, about the 7/16 bolt going thru the 5/8 tube, that kinda made me mad too, the worst part was the way they half welded the tube in the mount perch, a good flex on the undersized bolt thru the tube and snap would go the tube, the thickness of the steel on the motor mounts is actualy half that of the later 70-80's rubber mounts that i was going to use, i know that this stuff is aftermarket made in china, but you are right it's safety and quailty that is missing, it's a shame that you have to search for good parts for a build, it makes you want to just invest in the tools you need to make it yourself, but that costs way too much and takes too much time. I need to get some good advise on who sells the best parts soon, one day it's gona stop snowing and i want to drop my motor/tranny in the truck and put the doghouse back on.
