Orig track, flange, offset dimensions

[mickmate]

I have seen quite a bit of variation in the published specifications for track and other dimensions on 427's. This number is obviously bigger than the street cars but I see considerable variation on it other than that. One of the more common numbers I see is the competition and SC's having a 56" track. The number I'm after at the moment is a rear flange to flange dimension. Here's my maths...........
56" most common track I've seen
-10 1/2" (9 1/2"rim O.D (1/2 rim per side))
+ 7" (3 1/2" per side offset)
-3/4" (3/8" per side knockoff wheel adapter flange)
I make that 51 3/4" flange to flange or pretty darn close to an e-type. If any one can confirm those numbers and similar numbers, like front flange to flange, front a-arm lengths, upright dimensions, and so the list goes on...........this is the type of stuff that keeps me up at night!
Input and info appreciated.
Signed sleepless in construction!

[Bob Putnam]

At ride height, the Series I and II E-type is about 52.5" flange-to-flange. If you use an adapter that attaches to the original bolt-on flange, the normal method is to machine a bit extra off the back of the wheel. When Trigo makes their 5-pin system, their wheel has about 3.8" backspacing.

[mickmate]

Bob, I knew you'd be in on this. I would've been in touch directly but this is such a good place to share the info. So that looks like the 3.5" backspace they tell me the wheels have must include the .375" flange to make the 3.8" total. I'll call the lady at Trigo I've been pestering and try to confirm it with them. Sooooooo about those other dimensions. Peter said I should talk to you about them anyways. I'll be in touch as the mob er inlaws in CT are reconvening again shortly.
Cheers