it's worse than I thought

Dont cry yet. check the exhaust gasket. I bought rod bearings, a new piston and and a set of $3 exhaust gaskets for a 'bad' piston swap in my Mazda pick up. I was sure it was a rod knock, piston skirt or pin issue. turns out it was only the exhaust gasket that was bad! Sure sounded like a knock from hell to me. 4K for a rebuild seems pretty high so
I hope the builder will help out.