Tall decks were in buses and medium duty trucks (ie:dumps . . .) 366’s and 427’s…I need a 427 one.
If it’s an LS6, it’s a short deck. Also if it’s a LS6, I can’t afford it. 
If you can, send me the casting number and the block stamping. I have a good reference book and I can give you the history on it.
thanks