I have a 1986 C4, Z51, with 17" wheels from a 93. I am running 275/40-17 BFG-R1 tires for SCCA time trials/hillclimbs. I have no issues with it, but did get the Corvette specific 1" spacers from EZAccessories for it. These are billet aluminum, and hub centered just like the wheels - so a good tight fit. Once bolted on - you then have the studs from the spacer to bolt the wheels on - so it isn't like the spacers from the autoparts store that just lay over your existing studs.
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There is no problem a little horsepower can't fix!
C4s: 1993 LT-1 coupe, 6-Speed, White w/black
1986 L-98 Coupe, 4+3 Trans, Satin Black w/red-black interior - SCCA Time Trial racecar.
C3: 1979 L-48 couple, auto, Red w/doeskin interior.
https://www.c4vetteregistry.com/member_uploads/14301_14400/14327/100_5963_zpse01892a52014510161358r.jpg