I recently purchased a 76 Chevy C10 fleetside, shortbed, that has been lowered a bit.  The tires and wheels under it are stock 15" tires/wheels.

Anyone out there have any experience with what will fit for tires and wheels without rubbing under it?  

I'd like to go 15" 50 series on the back and 60's on the front but need to know about offsets etc to find wheels that will fit.  I'm not into the overwise wheels, just trying to find something that look's '76'ish for style.  

Any help would be appreciated.  

Just go to the tire and wheel store and they will help you. Most of what I have found is the stock off-set for your ride is going to be the same even on 10" wheels. If it sets to low then all bets are off as to the fender and wheel-well hitting. Custom off-set wheel big bucks, most case.  

Just go to American Tire Co, they have a good selection.  

I would but.. we're in a small town in Oregon.. the only thing we have here within a reasonable drive is a Les Schwab tire... and their policy if they mount the tire on the rim, you've bought it so no chance to see what just fits.. and what doesn't.  I was hoping someone out there with a 70-79 Chevy pickup had some experience with what does fit.    Right now on it is 235/75-15's all the way around.. there is lots of room.. but I'm hesitant to go start buying tires and wheels to find out they don't fit.  

I've had a few of these trucks and the one I currently have has a 20x10 w/ 4-5/8 back space on the rear  and a 18x8 with 4" back space on the front.  15" sizes will be the same offset.  My truck does sit pretty low (6-8 drop) so if yours isn't quite that low, off the shelf off set 15x10 & 15x8 will work fine.  You'll want to run a 295/50/15 or a 275/60/15  
on the back(the later would be my preference) and 245/60/15 on the front. Les Schwab has installed each and every set of custom wheels I've bought and I've never had a single issue with anything that didn't fit.