Looking for 18'' wheels for autocross 1st gen

I'm in the posses of building a 85 reg cab short box for Autorcoss and some street driving,I'm new to s10 so I'm a little lost on were to start  The  truck is going to have ls1 /auto out of WS6 bird ,we have UMI corner max kit for front , and JSM  3link in rear the rear is out of 01 blazer 8.5
I'm hopeing for some idea on wheel, The plan is  to run 275/40 /18 I would like to try a corvette rim if it could fit .
Thanks for the advice 

The C5 ZO6 rear wheels are a popular choice - 18 x 10.5" and weigh about 22 pounds IIRC. You may want to look for an 18 x 9 though if you're sticking with 275's, there's probably a C6 wheel in that size. If you plan to get serious with auto-x I'd do everything in your power to fit a wider tire or plan for a second set of race wheels with Hoosiers. 

I'm would  be interested in a wider tire .I just doint know were to start  to look at wheel ,what back set ,do I need spacers???
I'm trying to figure some sort of budget .
love the stance on yours. what are u running .and thank for the help!!

I'm not an expert on the Corvette wheels, but from my reading it sounds like most people run a 2.5" spacer with good luck. The 1st generation of trucks do have a bit narrower of a body than the 2nd generation, so keep that in mind when comparing tire fitment.

Good wheel and tire fitment can be a bit of a trial and error, but it isn't too hard to do. Honestly I recommend drawing it out while looking at some backspace drawings to get a feel for what all the different dimensions do. I almost always turn to google to find a diagram when I'm talking wheel offset and backspacing.

Take some measurements of your current wheel/tire and see what room you have to grow or shrink. I've taken white posterboard and wrapped it around the tire to simulate a wider wheel/tire and measure what that looks like.

Also most reputable tire companies will publish actual dimensions of their tires on the recommended wheel size. The 235/75R15 numbers are often more of a representation rather than an exact number, so the actual dimensions can help make more educated decisions.

I did all of that for my current setup and only have minimal rubbing in the rear on the one side. Could have gone another 1/8-1/4" larger spacer on my wheels and have no issues, but the rubbing is so rare I don't fret about it.

I run 275/40-17's on the truck and used to run that size on my car. After switching to 315/35-17's on the car, I recognized that 275's weren't enough on the truck.