1970 Duster, Trans-Am-inspired "Pro Touring" build

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They should be but I'd definitely check with Vlad to make sure.

Doctor Diff shows the same spindle for everything 73+.
I was able to connect with him through Instagram
 
That’s because only the shorter A/E and earlier B-body spindles are reproduced. The taller 73+ B/R and FMJ spindles are not reproduced, so the replacement spindles are listed for everything.

The caliper brackets for the single piston calipers are the same for each style, and can be used on any of the spindles that came with single piston calipers, so, ‘70-‘72 B/E, ‘73-‘76 A, and ‘73+ B/R/F/M/J (the taller ones). That’s true for both the 10.95” and 11.75” brackets, pin and slider style. Some of the calipers can’t be interchanged, like the 73+ B calipers are a bad choice for A-body conversions because of the brake hose location.

That doesn’t necessarily apply to aftermarket brakes though, because the taller spindle may change the ball joint/ UCA clearance to a larger aftermarket caliper. I would imagine Vlad would take that into account so only one style of bracket is necessary for both spindles because that would be easier for production, but that might not be the case if he only had one style of spindle to work with.
 
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Keeping with one year/make/model would be great in my opinion.
I do have a Viper brake kit from Cass for my Valiant that’s in chassis shop hell. That kit is way overpriced, IMO, and uses a rotor that only Cass sells. With Vlad’s way you can get rotors from NAPA or Amazon!
This way looks more economical and you could stay with one specific donor for calipers and rotors, purchase some Dr Diff hubs, and Vlads brackets.
 
After some researching on FABO I decided to go with some modern 18" Mustang wheels, 18x9 for the front and 18x10 for the rear. They are the "FR500" style and I purchased them new from OEWheelsLLC.com. One thing that drives me nuts about the current wheel/tire setup is the rears don't have quite enough backspacing so they rub the fenders but have over an inch of space to the leaf springs; I want to lower the rear of the car and get rid of the rake but the tires will just rub worse. So I did some measuring and used an online tire/wheel size calculator to make sure the new wheels I got for the rear would let me lower the car and not have to worry about rubbing.

Here are some pics of the mock-up for the rears. The center hub registers have a lip that I needed to grind down just a hair to clear the "hubs" on the rear axle flanges. The fronts are currently at a machine shop getting the hub registers bored through because the hubs on my '73-up front discs stick out too far and don't let the wheel seat on the hub.

I have a pair of 275/40-18 Continental ExtremeContact DWS-06 tires coming in the mail for the rear; my neighbor car guy friend made me an offer for 2 of the tires on his car he is taking off to mount bigger ones and the price was too good to pass up (those are 255/40-18 and will be going on the front of mine). I had been debating getting summer-only-rated tires for more grip at the track but winters are cold (consistently below freezing from Nov-March) here in northern CO and I like driving my Duster year-round. I don't drive it much in the snow anymore but summer-rated tires have warnings to not use them in freezing temps or the rubber can get damaged. I will eventually get dedicated track tires and wheels though for sure.

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So those wheels fit without relocating the leaf springs inward?
 
So those wheels fit without relocating the leaf springs inward?

Yes, still have maybe 1/2" clearance to the springs. The tires do rub a tad on the fender lips though even after rolling them (beating with a 1.5lb sledge lmao) as much as I could get the steel to bend. But it's not a lot, only occasionally when extreme cornering or hitting big bumps in the road, much less than with my previous wheel/tire combo and if you can see in my avatar pic which is most recent it sits fairly low. Much lower if you look back at the old setup and also consider these rear tires are 1.3 inches shorter in diameter. I need to check clearance to the inner wheel wells but I think these could use a few mm more offset to be ideal. They're meant to be replacements for 2010-2015ish Mustangs after all hence the low price and why I got them.
 
Another year gone by, better late than never? LOL...

Not much to report besides finally getting around to building up my 489 case with 3.55 gears and rebuilt clutch-type Sure-Grip over the past couple months. It was hell getting the gears set up and after weeks of trial and error they're in and they work but they make a slight whine. I ran out of motivation to pull it all apart a third time so I'm just gonna deal with it. I'll likely check the backlash when I go to change the gear oil after the ~500-mile break-in and adjust that if needed but that'll be the extent of it. I also need to reassemble the 2.94 ring and pinion back into my 741 case with the spare open diff I kept from an old 8 3/4" rear I pulled apart years ago.

Runs like a champ now though, Jim at Racer Brown ground my cam for these gears and it's like a different car now. Before with the 2.94s it ran decent off the line but compared to now it was struggling a bit until it got rolling around 20-30 MPH. Now you stomp on it from a stop and it just blasts forward like being shot out of a cannon. My rear tires are pretty wide and grippy so I haven't been able to test the sure-grip much on the street but I can definitely feel it's there when making tight turns. I'm excited to feel how it behaves at the track in hard cornering. Also curious what kind of ET it would put down at the strip, I don't think 13s are out of the question (which is pretty quick at over 5000' elevation). I'm just happy I don't need to worry about getting beat by stupid turbo 4-banger Subarus and Ford Focus ST's with loud exhausts and horrid crackle tunes anymore.

From here the car is next either going to get adjustable Fox (or equivalent) shocks or Mustang Cobra front disc conversion from Dr. Diff. I also want to convert to rear discs as the drums have always been a pain in my *** but the fronts need more stopping power first. All I need is a few grand for all that LMAO
 
Did you ever post any pictures with your 18” wheels, besides your avatar?

Any idea what your offset was on the wheels you bought?
 
Did you ever post any pictures with your 18” wheels, besides your avatar?

Any idea what your offset was on the wheels you bought?

Here's a link to the wheels I bought, you can read the specs there: Fits Ford Mustang Wheels - FR05B Mustang FR500 Rims - Black Mustang Rims Staggered

And a pic I took recently... sits a tad low in the rear now that the springs have finally settled, I'm debating whether to drop down one more slot on the rear shackles or putting back in the stock front hanger brackets

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Here's a link to the wheels I bought, you can read the specs there: Fits Ford Mustang Wheels - FR05B Mustang FR500 Rims - Black Mustang Rims Staggered

And a pic I took recently... sits a tad low in the rear now that the springs have finally settled, I'm debating whether to drop down one more slot on the rear shackles or putting back in the stock front hanger brackets

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Any issues with the front fenders with those wheels and tires? Clearance to the frame and UCA ok?

Hate to bug you again, but didn't see anything about that when I re-read your thread (not that I couldn't have missed it).
 
Any issues with the front fenders with those wheels and tires? Clearance to the frame and UCA ok?

Hate to bug you again, but didn't see anything about that when I re-read your thread (not that I couldn't have missed it).
No worries, happy to answer. I got some guidance from @72bluNblu on front tire size, they fit like gloves lol. No rubbing at all. I do have a touch of rubbing in the rear on the fenders with the 18x9" standard-offset Mustang wheels and 275/40ZR-18 Continentals even after folding over the inner fender lips (read: smacking with a 2-lb sledge lol). Note I swapped a 1967 B-body 8 3/4" into my car as well. Tires are pretty close (<1/2") to the rear leaves as well so that's about the max width that will fit in the rear on a Duster/Demon/Dart Sport.

From my experience previously running 215/65-15 in the front, those actually did rub just a hair on the fenders at full lock. Tire diameter seems to be the limiting factor on these A-bodies more so than width. Also going with 18s as opposed to 17s give extra clearance to the upper ball joints and allow more wheel width towards the center of the car.
 
No worries, happy to answer. I got some guidance from @72bluNblu on front tire size, they fit like gloves lol. No rubbing at all. I do have a touch of rubbing in the rear on the fenders with the 18x9" standard-offset Mustang wheels and 275/40ZR-18 Continentals even after folding over the inner fender lips (read: smacking with a 2-lb sledge lol). Note I swapped a 1967 B-body 8 3/4" into my car as well. Tires are pretty close (<1/2") to the rear leaves as well so that's about the max width that will fit in the rear on a Duster/Demon/Dart Sport.

From my experience previously running 215/65-15 in the front, those actually did rub just a hair on the fenders at full lock. Tire diameter seems to be the limiting factor on these A-bodies more so than width. Also going with 18s as opposed to 17s give extra clearance to the upper ball joints and allow more wheel width towards the center of the car.

Thanks!

I really want to run a 275/35R18 all the way around, but am struggling to find a wheel that works and doesn't cost an arm and a leg. And even with the right offset, sounds like a 275 takes a little work. Not opposed to messing with it, just easier if I don't have to.

If I am honest with myself, the rear has to have a 275 (or bigger) tire, the current 245 just looks too small proportionally back there (IMO), but the front would probably be fine with a 245/40R18 or the 255/40R18 you are running. And if they fit on a 18x9 +24mm wheel, that costs half what I am seeing for an 18x9 +35mm wheel, all the better.

Besides, part of the reason I want to run a square setup is so I can rotate the tires. But there is a good probability that the rear wheel will end up with a different offset which pretty much negates the idea anyway.
 
Thanks!

I really want to run a 275/35R18 all the way around, but am struggling to find a wheel that works and doesn't cost an arm and a leg. And even with the right offset, sounds like a 275 takes a little work. Not opposed to messing with it, just easier if I don't have to.

If I am honest with myself, the rear has to have a 275 (or bigger) tire, the current 245 just looks too small proportionally back there (IMO), but the front would probably be fine with a 245/40R18 or the 255/40R18 you are running. And if they fit on a 18x9 +24mm wheel, that costs half what I am seeing for an 18x9 +35mm wheel, all the better.

Besides, part of the reason I want to run a square setup is so I can rotate the tires. But there is a good probability that the rear wheel will end up with a different offset which pretty much negates the idea anyway.

I think @72bluNblu is running 275-wide fronts on his car, I believe he's using thin (1/4" or less) wheel spacers on "standard"-offset wheels to make it work.

I got my wheels from here: Home - I don't think they're actual legit OEM replacement wheels but the quality is good. Not as good as more expensive wheels and they're probably on the heavy side and surely made overseas but if you want affordable there aren't a ton of options. Mine are FR500 style for 1994-2004 Mustangs. Just had to take the fronts to a machine shop to have the center hub registers bored out to fit over my '73-up disc brake hubs. Rears fit fine with just some minor trimming of the hub registering "lip" using a dremel.
 
I think @72bluNblu is running 275-wide fronts on his car, I believe he's using thin (1/4" or less) wheel spacers on "standard"-offset wheels to make it work.

I got my wheels from here: Home - I don't think they're actual legit OEM replacement wheels but the quality is good. Not as good as more expensive wheels and they're probably on the heavy side and surely made overseas but if you want affordable there aren't a ton of options. Mine are FR500 style for 1994-2004 Mustangs. Just had to take the fronts to a machine shop to have the center hub registers bored out to fit over my '73-up disc brake hubs. Rears fit fine with just some minor trimming of the hub registering "lip" using a dremel.

I was running spacers at first, with the 13" DoctorDiff style cobra brakes I'm not running spacers anymore. I have 275/35/18's up front with 18x9's that are +35 offset. My wheels do touch the frame at full lock, but that's because my QA1 tubular LCA's don't have a steering stop. Not likely to be an issue with factory LCA's.

Initially I got away with not having the fenders rolled, but at my current ride height my fenders needed to be rolled and pushed so as not to cause rubs when compressing the suspension with the wheels turned sharply. You could probably get away with not having as much clearance as I've done, but I try to set mine up so I can drive "normally" and not creep over every bump and dip.
 
I think @72bluNblu is running 275-wide fronts on his car, I believe he's using thin (1/4" or less) wheel spacers on "standard"-offset wheels to make it work.

I got my wheels from here: Home - I don't think they're actual legit OEM replacement wheels but the quality is good. Not as good as more expensive wheels and they're probably on the heavy side and surely made overseas but if you want affordable there aren't a ton of options. Mine are FR500 style for 1994-2004 Mustangs. Just had to take the fronts to a machine shop to have the center hub registers bored out to fit over my '73-up disc brake hubs. Rears fit fine with just some minor trimming of the hub registering "lip" using a dremel.

Yep, been all over the forum reading and grabbing notes. Blu was the one that made me want to run 275 tires, love the look.
 
I was running spacers at first, with the 13" DoctorDiff style cobra brakes I'm not running spacers anymore. I have 275/35/18's up front with 18x9's that are +35 offset. My wheels do touch the frame at full lock, but that's because my QA1 tubular LCA's don't have a steering stop. Not likely to be an issue with factory LCA's.

Initially I got away with not having the fenders rolled, but at my current ride height my fenders needed to be rolled and pushed so as not to cause rubs when compressing the suspension with the wheels turned sharply. You could probably get away with not having as much clearance as I've done, but I try to set mine up so I can drive "normally" and not creep over every bump and dip.

I think I have an issue with steering stops as well. My current setup rubs on the frame at full lock, but I am only running a 245/45R17 on a 17x8 wheel with +30mm offset. Your wheels are almost a full 1" closer to the the frame than mine are, no reason I should be rubbing unless I don't have steering stops like I should. I did check them and it all looks like it should, so not sure why it is so far off. I plan to add some material someplace to reduce steering angle this winter while I am swapping the reinforce k-frame and adjustable strut rods in.

I am 99% certain I will be moving to 18" wheels in the future, my Scat Pack brake swap is looking too promising to drop it now. I'd love to do a 275, but I suspect in the end I will probably just run a 245/40R18 and a 275/35R18 on an 18x9 +24mm wheel.

Who knows, maybe in the end a $400 wheel verse a $250 wheel won't matter when it comes time to actually spending the money. If so, will go 275 all the way around.
 
Decided to give another update here... I've been in Georgia since March of this year and this month finally got to the point where I can work on stuff in my garage. I still need to find/build a place to store my extra parts, engines, transmissions, tools and such as half the garage is taken up by those currently.

Anyway the Duster is running great now after I retuned it for this elevation. Heck it ran pretty good before I tuned it. Due to the extra fuel demands though I have started approaching the limits of the Street Demon carb. At some point I will be swapping on a 750 cfm double pumper as this carb just isn't as tunable as I'd like. It gradually leans out as the RPMs increase but the air bleeds are not replaceable. I swapped the anti-pullover accelerator pump nozzle for a regular one which helped slightly but the AFRs are still not quite where I'd like them to be.

I still need to change the gear oil as the new 3.55 gear set has passed 500 miles. I'm going to measure the R&P backlash while the 3rd member is out and if it's less than .010" I'm going to increase it by 2-3 thou as it still makes a bit of noise. Iirc the instructions for the gears spec'd .010-.012" backlash and I think I set it a little tighter than that.

The current project is swapping the front brakes to the Doctor Diff Stage 2 kit. Earlier this month I flew to Jordan for a week to visit family and the day before I left (go figure) I decided to take the Duster for a quick spin. The passenger side caliper had always given me trouble with dragging ever since I converted to '73-up front discs, even after replacing the piston seal. Well it finally decided to seize on that last drive; on my way to the local supermarket I was smelling burning brakes and when I arrived there was smoke coming out of that side. I babied it back home and by the time I was pulling into my neighborhood it was locking up so tight the car was pulling HARD to the right and taking a good bit of extra throttle to keep moving. Got home and left it parked in my driveway for the next 3 hours or so just so it would cool off and not fill my garage with nasty brake fumes. It was smoking like crazy and the inside pad had what looked like glowing embers around the edges.
 
I debated back-and-forth between the factory-based brake kit and the Cobra-based one but after asking around on here I felt it wasn't worth the extra $400.

Full kit laid out in my living room. These slotted rotors will hopefully cool down quicker and they'll definitely look sweet through my 18" FR500 wheels.

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Progress so far, splash shields and caliper brackets are mounted. I also switched the knuckles side-to-side to run the calipers on the rear (bought the kit for that configuration). I want more clearance to the aftermarket sway bar end links.

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Slow moving since the Southeastern heat has ramped up. My garage faces west so even after the sun goes down there's a ton of radiant heat inside, not to mention the temp doesn't drop much at night. I also don't like to leave the door open with the lights on or it'll get filled with critters. I have the caliper installed on the driver side (no pic yet) but still need to do the passenger side and then attach the SS lines and bleed them.

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Also a tip for anyone getting Doctor Diff calipers... They come powdercoated black which is nice but the coating is thick enough that the calipers won't sit into the brackets. I had to file down the coating on the edges to get them to fit properly. After a few hundred miles I'll probably remove the clips and make sure the calipers still slide easily on the brackets.
 
Getting back here with a general update. I have a few hundred miles on the new front brakes and they're working great now that the pads are bedded in. I went to a Cars & Coffee event about a month ago held at Carolina Dragway and ran the car down the 1/4-mile for the first time since having the current engine and 3.55 gears. Track prep is killer there so there was zero tire spin off the line, impressive considering this car isn't set up for drag racing at all with high performance street all-seasons, Hotchkis rear leaves, stiff-*** torsion bars and zero traction aids but makes about 450 hp at the crank. I only did one pass but it ran a 12.65 ET at 108.15 mph. I'm happy with that and it should still get better once I finally get around to swapping the shorty headers and dinky 2 1/4” head pipes for Doug's long tubes and 3" pipes back to the mufflers and a more performance-oriented carb. Here's an in-car video of the pass:



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