Mike ,
I can 100% say that the TBI was not from a big block or a 4.3 L . As far as it being a 350 or a 305 ..... I can not see them pulling a 305 , they are not worth anything . I knew the previous owner of the van and set the deal up for the van to be hauled in and the previous owner even said it was a 5.7 , but with that being said ..... I have run into alot of people who think GM put 350's in every V8 camaro made