Need Shop in Ontario that will narrow a diff?

WOW so much info guys!! Thanks. "2darts" I saw your car last year at a Rockland show. I must say nice car! I ended contacting a few of these places including one here in Ottawa called D&D Perfromance who say they do this all the time and have all the right jigs and straight bars for it. My plans are for a A-Body stock lenght with 5 x4.5 bolt pattern. I found an E body rear on the cheap but.... So far I have been quoted 3 to 4 hours labour to do this at 85$ to 95$ on average per hour from these shops! YIKES! 3 shops wanted me to buy new ends and one of them said they should be able to re-use but cant guarantee it.

85$ dollar rear housing
85$ an hour*4 hours = 340$
160$ for new ends plus shipping
Rear axle package from Doctor Diff 300$ plus shipping

It is cheaper to get Doctor Diff or Mopar Madness in the states to build me one and ship across the border!!!! I think this is the route i will go.

Thanks everyone for the great info.

If anyone is looking for a place in Ottawa its D&D Performance In Chesterville just outside of Ottawa.