$650 for a used L6 motor? With a gold plated warranty maybe............ Absolutely; Anybody that has overhauled one and then had problems has to look in the mirror.......
I've paid less for complete cars that ran, some of them I drove a long time too. Maybe I advertised the broke 235 in my car in the wrong place - block is cracked, but it runs, I would have thought someone could use it for parts at least enough to pay what it will bring when scrap is high.
Get your 235 fixed, if that is what you want. A good 235 Chevy runs forever....unless you overheat it and crack the head.... There used to be brand new heads available....and UPS ran 235s in ALL of their delivery trucks - even had some special heads made up, if I remember correctly....