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

[MopaR&D]

More pics of the setup, still have about 1/4" clearance from the hard line to the k-frame

 

[MopaR&D]

Car was down for a few weeks because of a broken motor mount... I was running the incorrect fan with not enough clearance and it smacked the radiator top tank and cut a big gash into the core. Got the new radiator in with a shorter fan clutch and correct A-body-size fan and been commuting to work with it all this week...

 

[MopaR&D]

I also swapped the driver side motor mount for a solid, the engine doesn't move at all anymore lol. I put a big rubber washer between the engine bracket and "biscuit" to hopefully prevent any stress cracking in the block or K-member (I know it's not likely but I read a couple horror stories on here). I do feel more vibration especially through the steering wheel but each time I drive the car I don't notice it as much.

I've been constantly fine-tuning the carb as well since I got the new engine running but decided to try bumping up the timing from about 20 initial/36 total to 23 initial/39-40 total (not including vacuum advance). I was afraid that would be too much advance but it runs noticeably better and pulls cleaner in the upper half of the rev range with no audible pinging, even on regular gas (compression is only 9:1 with aluminum heads and 222/226 @ .050" cam, also 5000' above sea level). I also notice my AFR readings from my wideband have gotten a bit richer, further leading me to believe it likes the extra advance.

Only major downside so far is the gas mileage, last I checked before advancing the timing I'm getting about 11 MPG around town where my previous engine got 14-15 although it was higher compression with a smaller cam. Hopefully I pick up 1-2 MPG from the extra timing, also swapped in one stage leaner metering rods in the Street Demon carb a couple days ago so we'll see. I might make a trip down to Denver to visit my friend and drive the Duster, I haven't gone on a legit highway cruise with it yet since it got the new engine, curious how the gas mileage will be then too.

 

[MopaR&D]

Holy cow didn't realize it's been almost a year since my last post! I've mostly just been enjoying the Duster, driving the heck out of it and last summer did my first few time-attack events at Pikes Peak Int'l Raceway. I'm totally hooked and my focus has shifted entirely to making the car handle better. Last summer/fall I installed front and rear Hellwig sway bars (purchased through Bergman Auto Craft) which made a massive difference but I quickly realized the tire/wheel combo is the limiting factor currently. Here's a pic from a practice event back in February of this year.

 

[MopaR&D]

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.

 

[MopaR&D]

One tuning "mod" I did just a couple weeks ago was switching the vacuum advance from ported to manifold. The engine definitely likes it; it pulls harder from a stop with less throttle on light acceleration and runs a bit smoother, I could tell before when the throttle would close off the vacuum advance and it felt like the engine had to try harder, it's tough to describe. Anyway it works perfectly because with my cam and compression the engine pulls barely over 10" of vacuum at idle which isn't quite enough to pull in much vacuum advance but as soon as it get over 1500 RPM or so the vacuum comes up rapidly so when I decelerate or just barely crack the throttle when the car is moving the extra advance is still there. I'm also going to pull the distributor and redo the springs to bring the mechanical advance in earlier. Right now it's all in around 2500 RPM which works fine with my 2600-stall converter, IF I'm flooring it. If I'm not at WOT from a standstill the RPMs don't go that high and I think it would run better with the advance all in say around 2000 RPM instead.

Overall it runs like a champ, can't say enough good things about junkyard 5.9L Magnum short blocks. I have maybe 5000 miles on the engine now and aside from a little oil burning from the valve guides on startup after it's been sitting a while the engine is "tight". Performance is excellent and while more compression would be better it still runs DAMN good the way it is now and it's nice being able to run regular gas. Especially when it averages 13-16 MPG lol.

 

[DionR]

Been another year. Any updates?

Expected a picture with the new wheel/tire combo.

 

[MopaR&D]

Been another year. Any updates?

Expected a picture with the new wheel/tire combo.

I'm glad you posted, I need occasional reminders lol time flies. I will get some good pics of the car in its current state soon. Since last year I haven't done a ton of work to it, just been driving it and taking it to the track when I'm able. One mod was upgrading the rear leaf springs to Hotchkis units which I'm honestly a bit disappointed with; the rear of the car sits at a good height but they are still too soft for my liking. Even with my rear sway bar adjusted to the stiffest setting the car definitely prefers to understeer unless of course I do some left-foot braking mid-turn and give it some gas to swing the tail out but that's not the way to get fast lap times lol. I'm considering hitting up a leaf spring shop in Denver to see if I can have a leaf added and stiffen it up some more.

I also swapped out my 1.0" Just Suspension torsion bars (remember them? lol) for some 1.14" bars from Sway-A-Way, boy that really stiffened up the front end nicely but exacerbated the understeer issue. I really need to adjust my alignment for better grip, it has basically zero camber and way too much caster (over 8 degrees), probably my next adjustment then I'm gonna hit one of the early-season practice track sessions in February or March 2022 to see how much it improved and what next steps I need to take. I also need to buy some nice adjustable shocks, current cheapo replacement shocks are a joke they can't keep up with the higher spring rates.

Going into winter I wanted to upgrade the front brakes to 11.75" rotors with the later big-piston F-body calipers and also upgrade the upper A-arms but it's hard to say when I'll actually get around to it. I started a project to build a 440 for my D200 pickup and that's kinda the top priority right now in terms of spending money; I'm also trying to be careful with how much I spend as I want to save up to buy my own home. I've been living in my parents' house for about 6 years now and needless to say I'm really over it lol.

I did finally bite the bullet and ordered a set of Doug's D453 ceramic-coated headers after lusting over them for years, but again not sure when I'll get around to installing them. Autozone is having a 15% off online sale right now so I took advantage of it. I want to cut out the 2.5" X-pipe currently under the car and run 3" pipes straight off the header collectors and then reduce down to 2.5" right before the mufflers with no crossover. That way I'll have decent tuned secondary length which should boost low- and mid-range torque in addition to the improvement going from the current shorty headers with dinky 2 1/4" downpipes to long tubes. I really don't like the X-pipe sound anymore and everyone runs crossovers these days, I want to hear that REAL muscle-car V8 sound. Plus it's been proven that real power gains from X- or H-pipes is minimal if any in most cases.

 

[DionR]

Going into winter I wanted to upgrade the front brakes to 11.75" rotors with the later big-piston F-body calipers and also upgrade the upper A-arms but it's hard to say when I'll actually get around to it.

I guess I've always associated good handling with good brakes. So I end up lusting after the biggest brakes I can get. Running 13" Cobra rotors and PBR calipers off a C5 vette and I want more but then I need bigger wheels too.

I'm sure the 11.75" rotors are more than adequate. I just always seem to want more.

 

[MopaR&D]

I guess I've always associated good handling with good brakes. So I end up lusting after the biggest brakes I can get. Running 13" Cobra rotors and PBR calipers off a C5 vette and I want more but then I need bigger wheels too.

I'm sure the 11.75" rotors are more than adequate. I just always seem to want more.

I have looked at getting the conversion kit from Dr. Diff to run modern Mustang brakes but the price is pretty high, they are very appealing though. One benefit of taking my time with this stuff, as time goes on I may have enough money to afford that conversion and can skip the 11.75" rotors. I never felt that I needed to upgrade my brakes until I did an open-lapping event at the oval track I go to for track days where I was hitting 100 MPH coming off the banked turn then quickly had to slow down for a tight almost 180-degree turn in the infield area. I reached the point where pressing on the brake pedal harder didn't cause the car to slow down more quickly at those speeds and that was my indication, "OK time for bigger brakes!!" LOL

That was before I stiffened up the front springs and what happened a few times was my speed was too high going into that sharp turn and being on the brakes hard while also turning, the outside wheel would hit the bump-stop, unsettle the car then cause me to spin out. Hell of a fun time but clearly needed improvement.

 

[DionR]

I have looked at getting the conversion kit from Dr. Diff to run modern Mustang brakes but the price is pretty high, they are very appealing though.

That's why I built my own. Only took 10 or 11 years.

 

[MopaR&D]

That's why I built my own. Only took 10 or 11 years.

It's really just the hubs and caliper brackets you need to convert iirc, the rest of the parts are just off-the-shelf late-model Mustang stuff...?

 

[75slant6]

It's really just the hubs and caliper brackets you need to convert iirc, the rest of the parts are just off-the-shelf late-model Mustang stuff...?

There’s a guy on fb that builds brackets to make the SRT Brembos with on these cars too

 

[MopaR&D]

There’s a guy on fb that builds brackets to make the SRT Brembos with on these cars too

That wouldn't be the Vladimir guy by chance would it? I know a guy out here who bought some conversion parts from him for his Challenger (E-body not a new one lol) and they ended up not working, like they didn't fit... SRT Brembo calipers would be awesome though.

 

[75slant6]

That wouldn't be the Vladimir guy by chance would it? I know a guy out here who bought some conversion parts from him for his Challenger (E-body not a new one lol) and they ended up not working, like they didn't fit... SRT Brembo calipers would be awesome though.

Yeah the Vladimir guy. Sucks to here they didn’t work. Was he able to get them swapped with ones that work?

 

[MopaR&D]

Yeah the Vladimir guy. Sucks to here they didn’t work. Was he able to get them swapped with ones that work?

I don't remember exactly it was a while ago at the track the last time I talked to him, I think at the time he was just putting it on hold and looking at another option like Dr. Diff.

 

[75slant6]

I don't remember exactly it was a while ago at the track the last time I talked to him, I think at the time he was just putting it on hold and looking at another option like Dr. Diff.

I gotcha. If I hadn’t already dished out the money for my 13” Cobra stuff, I probably would’ve checked to see if he could make me a set for my Mii spindles. Course, then I would’ve needed to shell out more money for 18” wheels, too.

 

[go-fish]

Is there any confirmation on the quality of this Vlad guy’s caliper brackets working on an A-body? I am very interested but I don’t have Facebook. Does he have an Instagram account? @75slant6

 

[DionR]

It's really just the hubs and caliper brackets you need to convert iirc, the rest of the parts are just off-the-shelf late-model Mustang stuff...?

Pretty much. I got it done with Cobra rotors and C5 calipers. Cut some rotors down and got a couple of plates cut. Shouldn’t have taken the time it took, but it did.

 

[mpgmike]

Wow, you reminded me of a phenomenon I experienced over a decade ago when I was running my 1-man speed shop. Folks would buy stuff from me, then shove it under their bed. I was lucky to get a 30% feedback rate. You mentioned buying stuff, but you'll get around to installing it later. Seems people buy parts they intend to install, but often either never get around to doing it, or do it so many years later that ....

 

[go-fish]

@MopaR&D @75slant6
Is there any way I can contact glad outside of Facebook?

 

[MopaR&D]

Wow, you reminded me of a phenomenon I experienced over a decade ago when I was running my 1-man speed shop. Folks would buy stuff from me, then shove it under their bed. I was lucky to get a 30% feedback rate. You mentioned buying stuff, but you'll get around to installing it later. Seems people buy parts they intend to install, but often either never get around to doing it, or do it so many years later that ....

I don't typically take that approach, I only do it when a good deal comes up on a part I've wanted for a long time and I have some extra cash. I'm also attempting to buy up more expensive parts right now due to the current economic situation; between inflation, supply chain issues and materials shortages I imagine car parts are just going to keep getting more expensive as time goes on and I'm not betting on them getting cheaper again later on.

 

[75slant6]

@MopaR&D @75slant6
Is there any way I can contact glad outside of Facebook?

Here you go.

 

[go-fish]

Are the B-body brake caliper mounting brackets the same as A-body?

 

[MopaR&D]

Got my Doug's headers in the mail Friday, heck I could hang these up in my living room as a decoration lol they're almost too nice to put on a car. Really excited to get these in but I have other mods higher on the priority list currently.

I bought these now because Autozone is having a 15% off online sale right now and I have a feeling parts like these are going to get more expensive in the coming months. I paid $650 altogether for the ceramic-coated D453's.