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Which leafsprings for strip & street?


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Hiya folks

Next year I really need to replace the rear leafs on my 72 Mach1. Currently it has some cheapo replacement 4 leaf stock style units with an extra main leaf added by myself because they were saggy. These are very stiff although flattening out a bit now.

 

BA6E4659.jpg

 

I run bolt-on traction bars and Quick Times on the track.

 

It's a genuine street/strip car which will be running 13s next year and probably 12s in 2019. I think some compliance in the rear could help it a bit on the road & strip. I'm guessing 4.5 leaf standard eyes would work but I'm open to suggestion. So any recommendations?

 

Dunc

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Hiya folks

Next year I really need to replace the rear leafs on my 72 Mach1. Currently it has some cheapo replacement 4 leaf stock style units with an extra main leaf added by myself because they were saggy. These are very stiff although flattening out a bit now.

 

BA6E4659.jpg

 

I run bolt-on traction bars and Quick Times on the track.

 

It's a genuine street/strip car which will be running 13s next year and probably 12s in 2019. I think some compliance in the rear could help it a bit on the road & strip. I'm guessing 4.5 leaf standard eyes would work but I'm open to suggestion. So any recommendations?

 

Dunc

 

I would contact these people https://www.eatondetroitspring.com. They don't cater to racing per se but, they know more about springs than anyone else I know and may be able to help. I had a 12.70 @ 110 MPH 1971 Mustang in 1977.  I ran the stock springs with an xtra half leaf, good spring clamps, 50/50 shocks, and a pinion snubber, no traction bars. The car had 9" slicks.  Chuck

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Hiya folks

Next year I really need to replace the rear leafs on my 72 Mach1. Currently it has some cheapo replacement 4 leaf stock style units with an extra main leaf added by myself because they were saggy. These are very stiff although flattening out a bit now.

 

BA6E4659.jpg

 

I run bolt-on traction bars and Quick Times on the track.

 

It's a genuine street/strip car which will be running 13s next year and probably 12s in 2019. I think some compliance in the rear could help it a bit on the road & strip. I'm guessing 4.5 leaf standard eyes would work but I'm open to suggestion. So any recommendations?

 

Dunc

 

I would contact these people https://www.eatondetroitspring.com. They don't cater to racing per se but, they know more about springs than anyone else I know and may be able to help. I had a 12.70 @ 110 MPH 1971 Mustang in 1977.  I ran the stock springs with an xtra half leaf, good spring clamps, 50/50 shocks, and a pinion snubber, no traction bars. The car had 9" slicks.  Chuck

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Hiya folks

Next year I really need to replace the rear leafs on my 72 Mach1. Currently it has some cheapo replacement 4 leaf stock style units with an extra main leaf added by myself because they were saggy. These are very stiff although flattening out a bit now.

 

BA6E4659.jpg

 

I run bolt-on traction bars and Quick Times on the track.

 

It's a genuine street/strip car which will be running 13s next year and probably 12s in 2019. I think some compliance in the rear could help it a bit on the road & strip. I'm guessing 4.5 leaf standard eyes would work but I'm open to suggestion. So any recommendations?

 

Dunc

 

I would contact these people https://www.eatondetroitspring.com. They don't cater to racing per se but, they know more about springs than anyone else I know and may be able to help. I had a 12.70 @ 110 MPH 1971 Mustang in 1977.  I ran the stock springs with an xtra half leaf, good spring clamps, 50/50 shocks, and a pinion snubber, no traction bars. The car had 9" slicks.  Chuck

 

 

Sorry for the double post. Chuck

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Here is another option , I have 3 cars with calvert springs and caltracs.

https://www.calvertracing.com/index.php

 

I have noticed that all of the fast cars in my class (10-12s) run Caltracs. Are the split leaf springs ok to drive on the road?

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Here is another option , I have 3 cars with calvert springs and caltracs.

https://www.calvertracing.com/index.php

 

I have noticed that all of the fast cars in my class (10-12s) run Caltracs. Are the split leaf springs ok to drive on the road?

 

Yes  they work well just run a good adjustable  rear shock like a  QA1 . Then stiffen them up at the track and back em off for the street.

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Here is another option , I have 3 cars with calvert springs and caltracs.

https://www.calvertracing.com/index.php

 

I have noticed that all of the fast cars in my class (10-12s) run Caltracs. Are the split leaf springs ok to drive on the road?

 

Yes  they work well just run a good adjustable  rear shock like a  QA1 . Then stiffen them up at the track and back em off for the street.

 

Sounds good, if things work out financially in 2018 I might do that. My pb 60' is 2.24, I think it's an area where I can pick up quite a bit!

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I recently put CalTracs on my 66 F-100 and it was night and day better.  I even kept the original springs because I still tow and haul things with it.  You can always try the CalTracs first and add the Monoleafs later. See how it goes.  

 

Is that 2.24sec 60' with street tires or slicks? I was getting that with my Mach 1 on street tires leaving the line at idle(4-speed). It has 4 1/2 leafs and Lakewood traction bars. Any more rpm's and I'd just spin. I would have loved to run slicks but I don't have a safety loop and didn't want to start down that road of modifications.

 

IMG_4198.jpg

Mike

__________________________________

Black 1985 GT

Yellow 1973 Mustang Mach 1

Black 2012 5.0 GT, 6-speed, Brembo brakes, 3.73's

Wimbledon White 1966 F-100 Shortbed Styleside, 390ci, Tremec 3550, FiTech EFI

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Is there a traction device that you could use to improve traction but dont lose streetability or turning performance?. I dont mean for racing, but for spirited driving. If i dont have a traction bar do i have to worry about possibly breaking something if i launch the car hard with street tires?

 

Sent from my SAMSUNG-SM-G930A using Tapatalk

20160929_171923_edit2_small.jpg

 

1971 M-Code Mach 1 w/Ram Air, 408 stroker, 285/291 0.558" roller cam, Blue Thunder intake, TKO600, Hooker headers with electric cut-offs, FiTech EFI w/ RobBMC PowerSurge pump

Strange center section with Truetrac, 3.5 gear and 31 spline axles, 4-wheel disc brakes

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> Is that 2.24sec 60' with street tires or slicks?

Embarrassingly on Hoosier Quick Times, 275/60/15. I started the season on 255/50/17 street tyres and had so little traction I had to baby it off the line. I got used to doing that over 3 meetings, then I got the QTs & did another 3 meetings. I was told I would not need to burnout the QTs. Wrong - wheel spin at shift into second cost me my first possible final round win. I've been afraid to really hit the clutch hard as I was afraid of twisting the small input shaft plus I was trying to keep a consistent launch. I'm putting a big input in the gearbox this winter so I hope to hit it harder & drop the times some.

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