What is the largest tire you guys have been able to get under your 66 Chevelle. I have a stock 66 8.2 10 bolt posi. I right now have 275-60-15s which fit fine. I do not really want to go any taller but was wondering if I could go wider? Rims are 8 inch Cragar SS. Would even go shorter, say down to a 26 inch tire or so. The 275-60-15s are 28.

I dunno if you can go much bigger than that without going to a 17 inch or bigger rim. The smaller 15 inch rims like the hit the shock mount with a 10 inch wide rim out back is what I have heard. With a 17 people have fit 295s on 66-67's.

hmmm. Well I will be running drag radials. Have to see what is available in a 17 inch I guess. May just have to live with the 275s.

I dunno if you can go much bigger than that without going to a 17 inch or bigger rim. The smaller 15 inch rims like the hit the shock mount with a 10 inch wide rim out back is what I have heard. With a 17 people have fit 295s on 66-67's.
True, a 15X10 wheel with the proper backspace for a '66 will often have clearance problems between the wheel and the lower shock mount, but...
Rims are 8 inch Cragar SS

You can fit a 295/50-15 on the back of your '66, with no lip modifications and ample clearance... 295 will also fit on an 8-inch rim with NO problems (no reason to go to a 10-inch rim, just personal preference). BFGoodrich, for example, lists 8 inch wheels within the "recommended" rim widths, for their 295/50-15. These are about 26-1/2"+ tall...

Of course, you need to have the proper backspace on your rims... Compared to your current setup, you will need about 1/2"+ clearance minimum to your 275 to fit the 295 (figure the 295 will be about 1" wider, so 1/2" on each side)...

I currently am running a 67 12 bolt in my 66 with 15x9, 5"BS and 295x50's. They fit real tight and the wheel still clears the shock mount.

Hey now that sounds like it may be perfect. I would like to go to a 295-50 anyway. I do not think I have that much clearance though on the outside. Looks to me like I have more on the inside with my prestn 4.5 inch BS. I will try a 5 inch backspace and th 295s and see what happens. Gotta sale the other rims now! Thanks for the info all.

Hey now that sounds like it may be perfect. I would like to go to a 295-50 anyway. I do not think I have that much clearance though on the outside. Looks to me like I have more on the inside with my prestn 4.5 inch BS. I will try a 5 inch backspace and th 295s and see what happens. Gotta sale the other rims now! Thanks for the info all.

4.5" might be close, but if you don't mind trimming the lip a little (or rolling) it might be cheaper and easier that way...

5" BS might get a little tight on the inside wheel well/tub... Of course, with 5" of BS, you can always fine tune with thin (under 1/4") spacers (Not sure of sanctioning body rules for racing, but will probably be safe for street tires with good studs...

My 295's would definitely rub on the outside with 4.5"BS, because they are very close with the 5"BS. On the inside, there is only about 1/2" from the tire sidewall to the frame rail, so no more can go that way either. I originally tried 15x8's with 4"BS, but they rubbed on the outside. By putting more rim to the inside it allowed the sidewall to "relax" inward, hence no more rubbing. It is very tight both directions, but it does fit. If I could figure out how to attach pics I would, so that you could see what I mean. Guess the computer is smarter than I am.

cragars should have a 4.25 backspace. on my 66 275/60/15 m/t dr's rub on the wheel lip when the car is twisted alittle. thats with a 4.5 backspace 8 inch draglite. i don't think you want to a 17" if your looking to hook it up. i would love to stuff a 325/50/15 in there myself. but other than spacers or custom rims your choices for maxing out the usable space are limited. steve , what rims are you running ? any pics ?

I am running Cragar SS rims they are 8inch wheels with probably the 4.25 BS. I think I want to go to Weld pro stars anyway so I will look for 4.75BS maybe. Seems like I have more room on the inside than the outside right now. Not sure what is closer, the frame rail or the shock mount on the inside?