In 1988, I went to my local Chevrolet dealership to purchase either a LS-6 or LS-7 "crate motor". They were both available. The LS-6 was $2,800.00 and the LS-7 was $2,400.00. I chose the LS-6, due to the lower compression ratio. The LS-6 carried GM Part #366250 and had a engine suffix of "XAA" and the LS-7 was GM Part# 3965774 and had a engine suffix of "XCH". My driver's valve cover had a sticker on it that read "XAA". Hope this information helps you out.
