A well sorted 2.7 with webers ought to really sing. And, the market is insanely soft on the middle year cars. (likely due to poorly sorted, neglected examples. . .sounds like you found some SC's in that catagory

) I imagine every 2.7 on the road must have case-savers by now. So, if the price is right, go for it!
But reallize, you're on a slippery slope, and so you will soon hear the siren call of the understressed displacement of the 911SC.
MUHAHAhahahaha