Found my dads original 1971 duster!

I totally understand your point and that is why you paid them a PREMIUM for a rebuild.
I would be asking some questions, Heat will wreak havick on a flat tappet cam and especially one that is not broke in yet.
What kind of warranty did they give you?
Well when I asked about a warranty, they claim that engine rebuilds don’t really come with a warranty, because they don’t know how the engine will be “used”. This really didn’t make sense to me. They came with such high recommendations and to be honest, a few things happened that would make me never do business with them again. I’m praying that the engine will be ok. Maybe I should email them, so my concerns are in writing