I would suggest if your going through the trouble to install a 5.7 liter LS1 which can be had for around 1500/2500 dollars off the Corvette forums in the used parts sections...
An ls6 isn't much more either..
New an ls6 can be had for??? 4500 dollars..
If your spending the money your considering ...I'd say go with either an ls1, or ls6..
or maybe an ls2 if the computer could be setup
I don't know the details of the pcm of the solstice to the V8 so your really better going with the flow on the kits..(Ie. Reluctor wheel was a problem in ls2 to C5 swap that I remember)
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2008 Blk Corvette Z51 w/NPP and 2008 Silver AWD 304hp FE2 CTS