gsr head and ls short block cost less than a gsr long block but, you will break even once you get the lines and etc to do the conversion (if you do your own work)

Its not as expensive to build a motor as people think it is.
Weisco pistons & cometic head gaskett---------600
eagle rods --- --- --- --- --- --- --- 300 plus tax
Rod and main bearings-------------------------120
Thrust washers --- --- --- --- --- --- 40
Machine shop---------------------------------420 (bore, hone, hot tank & balance)
Block guard --- --- --- --- --- --- --- 100
Misc gasketts---------------------------------250 (depending where you get them...)
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Total===============================1830

Thats no labor if you have someone do it for you...