Author Topic: '68 Mustang Coupe Drag Car  (Read 118485 times)

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mbrunson427

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Re: '68 Mustang Coupe Drag Car
« Reply #150 on: October 14, 2025, 09:08:53 AM »
I see you added the leaf spring rear slider from Calvert. Do you know the theory behind how they work? Is it a better set up than stock style hangers?
I’m pulling everything apart for repairs and was looking at the rear sliders.
Thanks, Mike Gray

From my understanding it frees up the leaf spring and lets it move in the direction its looking to go, whereas a normal hanger rotates in a circular motion. When I set those up I made it to where the track on the slider points directly at the front spring perch. So if you were to take a laser or a string and run it along the slider path, it would point you right at the front spring perch. That allows the leaf spring to bow downward and the back of the spring narrows along the set plane of the spring. With a shackle, once the back of the spring narrows enough, it will begin to lift up along the motion of the shackle (and work against rear end separation). Not sure if this is making sense as I type it, seems easier to explain by drawing a picture.

I found this picture. This helps show what I mean I think.


There are also companies that make dropper sliders which will assist in rear separation. I didn't see any need of doing something as radical as that.
https://www.lpracing.net/product-page/rear-leaf-spring-separation-sliders

I'm not sure if you can run sliders in stock class?? But if this helps....when I pulled apart our car to put these sliders on, I found that large sleeves had been cut into the frame. It had polyurethane bushings in it that had been greased like crazy. Took me a while to clean up! I'm assuming they did this to allow the shackle to move as freely as possible.

Mike Brunson
BrunsonPerformance.com

mbrunson427

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Re: '68 Mustang Coupe Drag Car
« Reply #151 on: October 14, 2025, 09:12:25 AM »
Mike, I wrote a reply on the previous page as well about the perches. You might miss it because it moved on to a new page.
Mike Brunson
BrunsonPerformance.com

mike7570

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Re: '68 Mustang Coupe Drag Car
« Reply #152 on: October 14, 2025, 12:57:53 PM »
I looked it up in the NHRA rule book for stock eliminator and it reads the stock mounting points must remain. It looks like they wouldn’t be legal.

mbrunson427

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Re: '68 Mustang Coupe Drag Car
« Reply #153 on: March 16, 2026, 02:53:28 PM »
We got the Mustang put on my friends chassis dyno this weekend. I wanted to get everything tested out before we take the car out to a track, trying to build confidence in the car. Everything checked out well!

The torque converter didn't seem to love the load situation the rollers were giving it. We ran the car up to 6000 a couple times in 3rd gear but the dyno curve didn't make any sense. It pretty much went up to 340hp at 2500 rpm and completely flatlined. After talking with a couple people yesterday, I feel like I should have known better. Running a high stall torque converter on the rollers doesn't give great results. Really need a lock up converter to make that work. Getting dyno numbers wasn't the goal of the mission anyhow, this was more of a functionality test.

I didn't get any videos of running the car up to 6000. Wish we would have, but in the moment the last thing you're thinking of is for someone to start their camera.

https://youtube.com/shorts/CthiFNYngfE?si=q5lfs7C-YuaSIMLj



Mike Brunson
BrunsonPerformance.com

Stangman

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Re: '68 Mustang Coupe Drag Car
« Reply #154 on: March 16, 2026, 10:10:07 PM »
Sweet

66FAIRLANE

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Re: '68 Mustang Coupe Drag Car
« Reply #155 on: March 16, 2026, 10:16:12 PM »
I looked it up in the NHRA rule book for stock eliminator and it reads the stock mounting points must remain. It looks like they wouldn’t be legal.

But do they have to be used? ;D

mike7570

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Re: '68 Mustang Coupe Drag Car
« Reply #156 on: March 23, 2026, 09:18:10 PM »
I looked it up in the NHRA rule book for stock eliminator and it reads the stock mounting points must remain. It looks like they wouldn’t be legal.

But do they have to be used? ;D

NHRA has a saying “if it’s not explicitly approved then you can’t do it” . Not sure if it’s followed all the time, some reading between the lines goes on. I have seen another car with the sliders racing stock.