going to look at a truck need member help

[70cstjr]

Ok im not the smartest cookie in the jar, so i need some help
I know the truck isnt stock but just need some insight. Its a 69 4x4 with a 402bb and a 375 trans. i didnt know what kinda tranny that was if it was any good, the truck is 2500 bux, not much rust. it doesnt have the doors or the doghouse on. but all the parts are there, just not assymbled. thanks for any help this is a picture the guy sent me