Is there a difference in flywheels that came from a truck motor? Maybe even a larger truck motor? I have a '59 292 motor and I'm having a hard time finding a ring gear for it, I bought one off the internet and it would not expand enough to go over the flywheel, I found another one from NAPA and they list the I.D. of the gear. It looks like that gear will have to expand .15" to fit over the flywheel, too much? I think it is. I sent the other gear back and did not measure it but know it was too small, I heated it with torch and stuck 'wheel in freezer. The correct gear will have 146 teeth and the flywheel in question uses a 11" clutch. 

I'll throw in my two cents on this one,  My general "rule of thumb" for  "press fit" is.001 per inch of diameter, so, .015 would be acceptable for a 15" ring gear.  Be careful with the torch; 500 degrees is all it takes to remove the hardness from the heat treated ring gear.  Maybe....cool the flywheel as you said and oven the ring 200-300 degrees....should drop on. 

Y block flywheels are same except in hole locations for 11" clutches, but what i have found were some ring gears were too small in the internal diameter to expand far enough to fit, these i,m guessing were imports and wrong.


  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

If the teeth on the ring gear are only worn on one side, you can just flip it over. Save you the trouble of getting another one.

  Ron Lane,  Meridian, ID

I don't think you are suppose to do that. The flywheel and ring gear surface aren't a perfect 90 degree edge, thats why the ring gear has a small beveled/chamfer on one inside edge. That side goes against the fly wheel. 
I bought a Pioneer from Rock Auto and a little heat from a torch, light tapping with a hammer and it went right on..

I had this problem a few years back, I think most of the major suppliers were getting their ring gears from the same source they were made in mexico and
  they were slightly undersized  no amount of heat would make them fit.  they may have been sized for a small block Ford.  I finally found an NOS one from
  Joblot in New York but I'm not sure if they are still in business. 

you can flip over the ring gear people have been doing that forever.

Just flipped my ring gear this summer.Works fine.

Re Joblot Automotive. It's my understanding they have closed up in the last year or so..Unfortunately, I don't have any info as to where their stock may have gone..  Anybody know?..


Paul

Al's Ring Gears