Magnum 500 backspacing

[Dunerider777]

I am trying to find out what the correct backspacing is for a magnum 500 wheel for a 1966 GT350H. I am having my wheels restored right now and there are two different measurements on the set that I have that are a complete set of 5. The first measurement is 3 5/8" and the second is 4 1/8". I would like to find out what is correct so the wheels can be reassembled with the correct back spacing. Thank you.

[Rocket]

Not positive, but the 3 3/8 sounds like what mine are. Ron

[Rocket]

Correction, 3 5/8 should be what I said, Ron

[2112]

4-1/8" sounds close to what it would be for a 15x8" wheel.

[SHELB66]

Backspacing should be right around 3-1/2" to 3-5/8".  The 4-1/4" backspacing sounds like the measurement for a MoPar rim which many times gets confused with the Shelby rim.

Craig R.

[Brant]

3 3/8 BS for the ones that I have always measured.

[6s1640]

The typical back spacing is the 3 3/8, but I have seen 3 1/2 and maybe 3 1/4.  There can be a tolerance of +/- 1/8.  The Dodge rim can be restored to the GT350 back spacing with the 795C rim shell.  But the problem is the corrosion left on the rim shell will need to be repaired before or during the chroming process.  This is because the new back spacing exposes this area on the rim shell  that was previously covered.

Best of luck

Cory

[gt350hr]

   The most important thing are "no safety bead" on the "hoop" portion and that the "hoop" is put on the center "backwards". This means the "short" , drop center side of the wheel  faces "in" instead of out. This also requires that portion of the "hoop" to be polished before plating when it is not normally that way. This requires the tire be mounted "from the back side" 3-3/8ths is the Motor Wheel Co specification. Their "tolerance" at the time was +-.020 to SAI. I saw a print 40 years ago.
      Randy