My husband has a 383...?

engine in his car? I know it runs and is PERFECTLY tuned. He is in love with his car! (87 gta trans am with forged 383) but I hear he is selling the 383 alone... how much would one pay to have that? He is asleep and this guy is questioning me about prices and I don't know what is good - I'm not going to sell it for him - but out of curiousity how much would you buy it for it you needed it??