8 3/4 Brake drum face to leaf spring measurement needed.

[DartGTDan]

My '71 Dart GT has the factory installed 8 3/4" rear-end with stock location leaf springs.

Does anyone have a measurement from the (10" X 1 3"4) brake drum's face to the outboard side of the leaf spring?

I'm trying to see where different wheel backspaces will place a wheel in relation to the leaf spring(s).

 

[72bluNblu]

The wheel mounting surface to wheel mounting surface on a SBP 8 3/4 is 57 1/8”. Center to center on the leaf springs is 43”. The leaf springs are 2.5” wide, so, outside to outside on the springs is 45.5”

57.125”- 45.5” is 11.625, divided by two so it should be

5.8125” (5-13/16”) from the WMS to the outside of the spring for an A-body with the stock spring locations and a SBP 8 3/4.

My ‘71 Dart GT has an A-body 8 3/4 with BBP axles (11x2.5” drums) and that measurement is 6” on the “tight” side, which also makes sense given the change in track width from SBP to BBP. The other side is closer to 6 1/8”. Which brings up an important point.

You have to measure YOUR car. Because with body tolerances being what they are anything +/- an 1/8” from 5.8” would be well within spec. And there are cars out there further out of spec than that. Just because my or someone else is else’s car measures something doesn’t necessarily mean yours will.

 

[DartGTDan]

Thanks 72bluNblu.

I'm still kicking around the idea of body colored steelies with the red line dog dishes (a Fathers Day present from my wife).

I see SummitRacing has Wheel Vintiques 15" X 6" with 3 3/4" back space (which is nearly identical to the 14" X 5 1/2" with 3 3/4" back space factory Rallyes). They also have 15" X 7" with 4 1/4" back space (rear). I think the 15" X 7"s will work out back, but I need to do more measurements after our road trip to St Ignace this weekend.

 

[72bluNblu]

15x7’s with 4.25” backspace will work out back. If you wanted to max out your tire size though you’d want more like 4.5” of backspace on a 15x7. Just depends on how wide you want the rear tires to be.

 

[halfafish]

I see SummitRacing has Wheel Vintiques 15" X 6" with 3 3/4" back space (which is nearly identical to the 14" X 5 1/2" with 3 3/4" back space factory Rallyes). They also have 15" X 7" with 4 1/4" back space (rear). I think the 15" X 7"s will work out back, but I need to do more measurements after our road trip to St Ignace this weekend.

As info, I ordered these exact wheels for my 66 Valiant from Summit. The rears arrived a few weeks ago but the fronts were backordered and I kept getting conflicting and repeatedly changing backorder ship dates. I finally called Wheel Vintiques to see what was going on, their guy said they were waiting for the barrels to come from their vendor so they could assemble the wheels. Anticipated completion date to get them built and to Summit who could then send them to me was the middle of October or so.

Coker has the same wheels but they don't have free shipping. I decided to bite the bullet and order them so I could move forward with my project. It cost me an extra $125 but I figured it was worth it. The rear wheels, along with the new front and rear tires (Cooper Cobras) are sitting here. The front wheels from Coker arrive tomorrow. I will be able to confirm in a few days that they fit. I did a LOT of measuring, I feel confident they will be OK.

I currently run 205/70/14 on the front on a 14x4.5 steelies (yes, I know it's too narrow - that's why it is getting replaced). The current rears are 245/60/14 on 14x7 with 4.5" backspace and they fit just fine. I needed new tires and wheels so decided to go with the 15" to get better tire selections. The 15" tires are only a hair wider than what I'm running right now, so I should be good. I will let you know for sure when I get them mounted, balanced, and installed.