Magnum 500 15x10 Backspacing

[shawnmd]

Well I went ahead and ordered 2 15x7 (4.25" backspace) Magnum 500s and two 15x10 (5.0" backspace) for my 69 Charger.  I had reseacrhed the size on this site and Moparts.  I had read that a 5.5" backspace would work on the rear as well but might be a little tight.  Anyway, after waiting for 8 weeks to get the wheels, my dealer calls to tell me the 5.0" backspace wheels are backordered and that Wheel Vintiques was wondering why I ordered the 5.0" backspace instead of the 5.5" backspace for the Charger.  They said that they usuaaly recommend the 5.5" for B-body mopars.
So last night I went out and measured my backspace from the face of the drum to the springs and the inner wheel well, and the shortest distance was 6.75".  With a backspace of 5.5", that leaves me 1.25".  Now I understand that the tire bulge will use some of that, but I should still have enough room.  The tires are Cooper Cobra's at 295/50R15 which tend to be slightly skinnier than the BFG's in the same size.
What do you guys think?  Will they fit?

[Troy]

They should. Usually, an 8" rim has a 4.5" BS so, if you want the tire centered in the same spot it was originally in then you'd need a 5" BS for a 9" rim and a 5.5" BS for a 10" rim. Watch the spring clearance with the wider tire/rim and large BS. If you don't get enough BS then you'll hit either the wheel well lip or the wheelhouse every time you hit a bump (so don't just measure clearance to the lip).

Troy (Moving this to the right section)

[chargerboy69]

I run a 10"wide wheel with a 5.5" backspace. No problems.

[68RT4ME]

I run a 10"wide wheel with a 5.5" backspace. No problems.

Post a pic please as I will have to order my wheels in the coming months and have been thinking about that size.