average size to narrow a 8.75

[USCG Charger]

whats the average narrowed length of a 8.75 you cut for a Dart thats mini tubbed and springs relocated?

Rear wheels:
18x9
275/45/18
27.8"

with that being said... Do i need to move my rear back 1" to get those to fit?

[A13Dart]

28 inch diameter will fit at the stock location.  30 inch could fit with rear moved back 1 inch.  (67 - 69 Darts )

[65 SIGNET]

You need to set your wheels in the wells and measure from wheel to wheel, and use that as a base to cut your rear end to size, i have 65 and cut my to 50 inches for 15x8 rim 5.5 offset  depends on what year also

[USCG Charger]

the problem I have is:

When I place my wheels under there where I want them and measure it... and give it to Dr. diff.... will he know to add my brakes to the measurement? B/c wheel to wheel will not be the exact measurement w/the drum brakes added to it right?

JAson

[jbarker]

Hey Jason-  You're right- you DO need to account for the thickness of your drums.
Set your wheels in place and measure from the inside surface of one to the inside surface of the other like 65 Signet said.  Rear drums are usually about 1/8" thick at the axle flange, so I subtracted 1/4" total from my wheel to wheel measurement to get my axle flange to axle flange measurement.  Actual thickness of the brake drum material is the only thing that you need to subtract here.  The width of your shoes will not affect total width measurement (axle flange to axle flange).  Make sense?
Also, just tell Dr. Diff what rear brakes you plan on using, and he will know how far out from the axle tube your axles should extend.
Not to muddy the waters here, but...
Most people say that a 28" wheel will fit with axles in stock location.  That was not the case for my car (71 Dart Swinger)-maybe my car is unusual.  I used a tire with height of 27 3/4" and it just barely rubs the front of quarter panel.
I have a moser-built Dana 60, and there is 1 1/4" between diff cover and fuel tank, so I do have room to move the axle back a bit, which is what I'm planning on doing.  Let me know if any of this is unclear, cause you wanna get those measurements spot-on the first time!

[USCG Charger]

Hey Jason-  You're right- you DO need to account for the thickness of your drums.
Set your wheels in place and measure from the inside surface of one to the inside surface of the other like 65 Signet said.  Rear drums are usually about 1/8" thick at the axle flange, so I subtracted 1/4" total from my wheel to wheel measurement to get my axle flange to axle flange measurement.  Actual thickness of the brake drum material is the only thing that you need to subtract here.  so its not the thickness of the entire dum brake (4-5" or so)?The width of your shoes will not affect total width measurement (axle flange to axle flange).  Make sense?
Also, just tell Dr. Diff what rear brakes you plan on using, and he will know how far out from the axle tube your axles should extend.I was planning on running bbody drum brakes off of a 69 roadrunner
Not to muddy the waters here, but...
Most people say that a 28" wheel will fit with axles in stock location.  That was not the case for my car (71 Dart Swinger)-maybe my car is unusual.  I used a tire with height of 27 3/4" and it just barely rubs the front of quarter panel.I was thinking that since I'm about to do my relocation I'll just move the box back 1" or so.....if I move the box back on the frame one inch how do I do the rear hanger?
I have a moser-built Dana 60, and there is 1 1/4" between diff cover and fuel tank, so I do have room to move the axle back a bit, which is what I'm planning on doing.  Let me know if any of this is unclear, cause you wanna get those measurements spot-on the first time!

[b][/b]

[jbarker]

I think you got it.  When measuring for total axle length, you don't subtract the "thickness of the entire drum brake (4-5" or so)"
Think about it- the only thing that is physically between your wheel and the axle flange is the face of the brake drum.  And since the drum basically fits over the axle flange,  the only thing that keeps the wheel from actually touching the axle flange is the 1/8" or so thickness of the brake drum. 
When I measured, I set the wheels under my car and measured 58 1/8" from inside of 1 wheel to inside of the other.  I then subtracted 1/8" each side to account for drum face thickness.  So I told Moser to set it up at 57 7/8" from outside face of one axle to outside face of the other axle.  Your drums should essentially be the same thickness. 
Measure the width of the shoes you will be using and let Dr. Diff know so he can make your axle housing the correct width.
Regarding the rear hanger, I think you'll have room to move it back one inch on the frame, but I haven't had to do that yet, so I'm still uninformed on the topic.  Let me know if anything is still unclear.
-Jay

[65 SIGNET]

It also depends on what you are using the car for, if its for street use moving the rear end back a inch will be good, if you are going to drag race you may want to leave it in the stock location for better traction

[ab7fh]

30 inch could fit with rear moved back 1 inch.  (67 - 69 Darts )

What's different in the '70+? I was thinking of moving the axle back in my '70 for additional clearance. Is there something I'm not taking into consideration?

[jbarker]

30 inch could fit with rear moved back 1 inch.  (67 - 69 Darts )

What's different in the '70+? I was thinking of moving the axle back in my '70 for additional clearance. Is there something I'm not taking into consideration?

I'm pretty sure that fitting a 30" tire after moving the rear back an inch applies to your '70 as well. 

[DartCustom496]

I moved mine back 1.5 inches, with a 29inch tire i have 1 1/4 in front of tire to the edge of the wheel opening,when I wnet to narrow my housing i used my friends tires and rims , set them under the car, measured from inside of rim flange and came up with overall width of housing .