Good Deal on a 383?
If you can pull the heads and spin it and it looks OK, I'd offer him $2,800 and stand on $3K unless you're getting a 3.55/3.91 SG. Since you're already planning on suspension upgrades, you can change your plan to work with the added weight of the big block. It's already got an aluminum intake on it, add the aluminum water pump and housing, put the battery in the trunk, and you're pretty close to the weight of an iron SB on the front end. Put the right cam in it and you're golden. There's no replacement for displacement.
I WISH I only had $3K in mine with headers, carb, intake, dizzy, 8 3/4, etc..