This '65 Mustang hides a modern secret underneath

J.G.
By J.G. Pasterjak
Aug 5, 2021 | SCCA, Mustang | Posted in Features | From the Aug. 2021 issue | Never miss an article

Photography by Perry Bennett unless otherwise credited

"Understand, this is all happening within about a 90-minute window,” explains Mark Stevens. He could be talking about a drive to the airport, or a leisurely dinner, or a couple of episodes of his favorite TV show. 

But in this case, Mark is describing how he went from first becoming enamored with the Pro Touring aesthetic to embarking on the project that would result in the insane-looking 1965 Mustang coupe you see here.

To be fair, Mark wasn’t going in completely cold, as he had quite a history with motorsports prior to this momentary lapse on eBay. His past included shifter karts, and he had always wanted to run the Baja 1000, so he, uh, did. Like, he just went ahead and made a plan and did it–a feat he relays in the fairly casual manner of someone telling you how they built a nice deck off of their family room.

[The BRE Datsun 240Z That Took on the Baja 1000]

But Mark just gives off that vibe of someone who doesn’t try too hard to avoid a challenge. His smarts and determination usually pull him through whatever he sets his mind to.

Hellraiser

A family member introduced Mark to autocross a few years ago, and that ignited his latest competitive fire. “The thing about autocross is that sometimes someone with a little bit of driving ability will show up for the first time and come within maybe a second of the fast drivers and think, ‘Hey, I’m pretty good at this,’” Mark says. “But then they come back and realize how hard that last second is to get. And the last few tenths and hundredths are even harder than that. I love that level of execution you have to operate at to succeed.”

Mark’s newfound passion for autocross led him to an S550-chassis Mustang GT built for the SCCA’s E Street Prepared class. But then one fateful night on the internet–how many insane stories start that way?–landed him with the bonkers project you see here. 

Those giant flares–actually just repositioned stock fenders, more or less–cover today’s latest tech, including a full Motec setup. 

As Mark tells it, “I came across some cool Pro Touring builds just browsing around. And I thought, ‘How cool would it be to have those looks and presence with the hardware from my 2016 Mustang?’ And I never really talked myself out of it, and within about an hour and a half, I had made what I thought was going to be a rejected offer on a roller 1965 Mustang on eBay that was accepted. I sort of called my own bluff.”

Mark calls this creation his “first scratch build,” but looking at the car, you’d think a legacy shop put it together for SEMA. “Being a Baja guy, I really like the Trophy Truck aesthetic, and those things are just ridiculously overbuilt,” he explains. “So I wanted to bring a lot of that feel and detailing to this car. So if those trucks–which basically destroy themselves over 1000 miles of hard running in the desert–are overbuilt, this thing in an autocross situation is just really reliable.”

What Lies Beneath

Part of that reliability comes from the fact that, while this creation wears a 1965 Mustang body, it’s mostly modern hardware underneath. Front and rear subframes are from a 2020 Mustang GT350, and a third-generation Coyote engine provides the power.

[Meet our 1965 Mustang vintage racing project car]

The crazy flares were necessitated by the width of the modern Mustang suspension, but the overall length of the 1965 car was remarkably similar to the modern version’s. “I think the driveshaft length changed by less than an inch,” Mark recalls, meaning the overall rolling footprint of the car is almost identical to a late-model Mustang.

It’s not just bolt-on hardware from there, though, as the front suspension in particular has been heavily revamped from stock. Instead of using the GT350’s factory struts, Mark designed and fabricated an A-arm front end using modified versions of the GT350 spindles. It features custom adapters mating those remachined spindles to upper arms of his own design. “Freeing the subframes from the limitations of the stock body gave me some options to optimize things without packaging restrictions,” he explains. His gift for engineering and fabrication seems to only be exceeded by his gift for understatement.

The brake system also received some attention, with the GT350’s stock Brembo calipers squeezing a set of 15-inch, two-piece rotors from Racing Brake. No vacuum booster resides on the firewall, however. Instead, braking power assist is provided by a Bosch electric booster repurposed from a wrecked Tesla.

The Changeling

Mark says that the reconfigured ’65 Mustang drives like its modern counterpart. Indeed, the weights and balances are similar, and all of his additions were improvements to what is essentially an S550 Mustang wearing a cool, retro outfit. 

He describes most of his remaining sorting plans as “a bunch of little stuff, just like any other CAM car,” referring to the SCCA’s anything-goes pony-car division, Classic American Muscle, where his Mustang currently sees autocross duty. 

Mark fit late-model Mustang cradles front and rear while fabbing custom A-arms for the front suspension. The Coyote engine currently runs through a 10-speed automatic, but a T56 is coming soon. Photography Credits: Mark Stevens (suspension and engine)

Mark does have plans for a fairly major transmission swap, though. “The 10R80 automatic just sucks in this application,” he admits. “Even with HP Tuners software controlling it, there’s just so many variables that I never could get it to work 100% predictably. You’ll set a lockup value for the converter and, for whatever reason–maybe slightly different fluid pressures or temperatures–there will always be at least a little variance. The data logs on the output side never quite matched what I was asking for on the input side.” 

Ultimately, Mark plans to solve his transmission frustrations with a six-speed T56 manual gearbox paired with a McLeod twin-disc clutch. 

It takes a lot to stand out in a CAM class full of wild, no-compromise versions of classic muscle machines, but Mark’s Mustang manages to be one of the most extreme examples on a grid full of extreme examples. Pretty impressive, especially for a 90-minute decision.

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Comments
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Ian F (Forum Supporter)
Ian F (Forum Supporter) MegaDork
7/2/21 8:15 a.m.

You are using the term "hides" rather loosely here... 

BA5
BA5 GRM+ Memberand Reader
7/2/21 10:23 a.m.

I spy with my little eye..... a lot of hours on an mill!

Mr_Asa
Mr_Asa UberDork
7/2/21 10:52 a.m.

I gotta say, I'm not a fan of the "flares"

Rodan
Rodan SuperDork
7/2/21 11:07 a.m.

In reply to Mr_Asa :

+1

I love box flares, but those are not attractive.

Mr_Asa
Mr_Asa UberDork
7/2/21 11:10 a.m.

In reply to Rodan :

Maybe because they aren't box flares?

thatsnowinnebago
thatsnowinnebago GRM+ Memberand UltraDork
7/2/21 1:06 p.m.

The front shock mounting is very interesting. Is that so the LCA can be lighter because it doesn't need to deal with the load from the coilover?

pres589 (djronnebaum)
pres589 (djronnebaum) UltimaDork
7/2/21 1:18 p.m.

Looks like a Transformer stuck half way between car and robot.

300zxfreak
300zxfreak Reader
7/2/21 3:19 p.m.

I'd have to agree with the aesthetics critiques here, not a fan of the look.......at all. I guess it's really a case of form follows function to some extent, but I think it could have been handled a lot better.

BA5
BA5 GRM+ Memberand Reader
7/3/21 12:32 p.m.

I think the flares look really cool from certain angles, but they do look kinda goofy from others.

BA5
BA5 GRM+ Memberand Reader
7/3/21 12:32 p.m.

I think the flares look really cool from certain angles, but they do look kinda goofy from others.

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
7/3/21 12:37 p.m.
thatsnowinnebago said:

The front shock mounting is very interesting. Is that so the LCA can be lighter because it doesn't need to deal with the load from the coilover?

It looks like a repurposed strut suspension, I would think that the lower ball joint and bottom half of the upright are not designed for chassis loads.  Loading the upper control arm makes sense, because that puts the loads into the upright how it was engineered to.

 

Countingcrowbars
Countingcrowbars UltraDork
7/4/21 11:25 a.m.

Let me guess... Ls powered? Don't have the unlock yet. 

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
7/4/21 11:28 a.m.

In reply to Countingcrowbars :

Worse, Coyote.  That means there is no mounting hole in the block for the clutch linkage AND there is no place for a power steering pump to attach.  wink

maj75 (Forum Supporter)
maj75 (Forum Supporter) Dork
7/5/21 2:12 p.m.

Not pleasing to my eye.  I've seen a ton of custom Mustangs, and this one got beat with an ugly stick.  I get form over function, but when you spent this much on function, to ignore form seems purposeful.

mainlandboy
mainlandboy Reader
7/5/21 2:37 p.m.
Mr_Asa said:

In reply to Rodan :

Maybe because they aren't box flares?

Agreed. Flares would have looked nice, but this is just moving the fenders and quarter panels ~8" outboard, with no smooth transition to the doors.

captdownshift (Forum Supporter)
captdownshift (Forum Supporter) GRM+ Memberand UltimaDork
7/5/21 3:01 p.m.

I for one welcome our Hoonicorn of autocross overlords. 

TIGMOTORSPORTS
TIGMOTORSPORTS Dork
8/9/21 9:09 p.m.

The magazine cover photo of this car - is one of the best cover photos I've seen. Nailed it.

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