A guy gave me 2 '64 327's..........so to answer your question it all depends on how badly someone wants it......and what kind of shape its in. If its been bored a couple of times and the steel crank ground and its in need of a rebuild again then its not worth much. Only way to tell is to tear it down. I personally wouldnt give a plug nickle for any engine that I can't at least mic the crank and bores.
I paid 100 bucks for it because the guy told me it was a 4 bolth 350. 2 years ago and it ast in my yard under a tarp. started tear down tonight and it's in good shape. has been bored 30 over and has forged aluminum pistons. plus i sold the set of bad heads off of it for 75 bucks.
"because the guy told me it was a 4 bolth 350"..........I rest my case, for what it's worth. Never take a strangers word for it, if the engines out of the car/truck at least pull the pan. If he won't let you then take a walk. He probably didn't know what it was either (maybe??) Anyway $100 bucks - $75 for the heads ain't a bad deal.
Question....you're replacing a "destroked 350", what kind of crank is in it to de-stroke it? Unless its something custom ground then its most likely a large journal 327 crank which makes it a 327.....or 331 w/ a .030 bore.
Yes the crank in the 327 you bought has a sm jrnl steel crank......but what kind of crank is in the de-stroked 350 that you are replacing? It can't be a sm jrnl forged because all 350's have large jrnl cranks.....unless you have bearing spacers.