Rear leafs - what spring to use for good launch & good street manners - Ford Muscle Forums : Ford Muscle Cars Tech Forum
 
LinkBack Thread Tools
post #1 of 11 (permalink) Old 02-26-2006, 10:40 AM Thread Starter
Registered User
 
Join Date: Feb 2003
Posts: 1,211
Rear leafs - what spring to use for good launch & good street manners

My car is a mostly street driven 65 Mustang fastback with a stroked 351W (about 475FWHP), G-Force (T5) 5spd. and drag radials. I was running a 4.33:1 ratio but will be changing to a 3.89:1 ratio when my new N-case and 31 spline axles are ready in a few weeks.

I am planning to replace the very tired (2.5&quot rear leaf springs, and am trying to decide what spring and spring rate to use. The car sits about an inch lower than stock, and has the Shelby A-arm mods, big sway bar etc. I realize this is far from ideal for straight-line traction, however I am looking for a balance between traction and a car with decent road manners. When I take it to the strip I will run a real slick, and hope to run somewhere in the 11's

From what I have read the Flexi-Form springs and Cal-Tracs make a great combination for drag racing. Is anyone using this combination on the street? Are they okay? Will they last?

Perhaps these are over-kill??? and stockish steel leafs would be fine??? I would like to hear your opinions, and recomendations for spring rate.
slow-poke is offline  
Sponsored Links
Advertisement
 
post #2 of 11 (permalink) Old 02-26-2006, 05:23 PM
Registered User
 
Join Date: Mar 2005
Posts: 203
Rear leafs - what spring to use for good launch & good street manners

I've found adding 1.5 leafs to the stock combination works well - half leaf going forward from the axle.
mattrobison is offline  
post #3 of 11 (permalink) Old 03-11-2006, 08:33 PM
Subscriber
 
Join Date: Feb 2006
Posts: 91
Rear leafs - what spring to use for good launch & good street manners

Replace the second spring with a longer spring from a spring shop that will extend forward past the center line of the front spring bolt by 1 inch. If you use slapper bars extend the bar so that the snubber lines up with the center of the eye(front spring bolt) and has 1/4 inch clearance on pass side and 1/2 on drvs side......the combo works good for 11.20s and up!

Never shoot your mouth off unless your brain is loaded.
quickshift is offline  
 
post #4 of 11 (permalink) Old 03-12-2006, 09:43 PM
Registered User
 
Join Date: Jul 2002
Posts: 398
Rear leafs - what spring to use for good launch & good street manners

I went from a 5 leaf to the mono leaf, better ride and responce. the mono leaf has no binding and fits great with the caltracs. I think your suppose to take all the preload out for street driving but I havent tried that yet, I run the bars loaded at all times.
fastback.brian is offline  
post #5 of 11 (permalink) Old 02-06-2008, 11:24 AM
Registered User
 
Join Date: Apr 2004
Posts: 88
Re: Rear leafs - what spring to use for good launch & good street manners

Where do you get the Flexi-form springs?

Are they safe for street use?

Thanks
LXguy is offline  
post #6 of 11 (permalink) Old 02-06-2008, 02:05 PM
Registered User
 
Join Date: Apr 2002
Location: Merkel, Tx
Posts: 9,251
Re: Rear leafs - what spring to use for good launch & good street manners

I'm running Caltracs, stock leaves (41 years old), Rancho shocks. I'm in the low 1.6 60's foot range. The car drives fine, either with the Cals set for the track or loose for driving around.




1967 Falcon 4 door 351C - 70 Mustang 351C
Owner built, owner abused.
ckelly is offline  
post #7 of 11 (permalink) Old 02-06-2008, 02:21 PM
Subscriber
 
Join Date: May 2003
Posts: 1,305
Re: Rear leafs - what spring to use for good launch & good street manners

Jeff,
A buddy of mine is running Cal-trac mono's and swears by them.
He went from a 1.59 to a 1.54 with ONLY switching from superstock mopar leafs to the mono's in his 67 Barracuda.
It made me raise my eyebrows too.
He drives the car about 1000 miles a year and says he has not noticed anything in terms of ill street manners with the mono's.
Next year, I'll be switching to the mono's.


347, world jr heads, TKO600RR, 4.11 31 spline DL, comp cams solid, pro-systems 750DP, Vic Jr. 100 shot of NOS with old 306 = [email protected]
Thordane65 is offline  
post #8 of 11 (permalink) Old 02-06-2008, 05:45 PM
Registered User
 
Join Date: Aug 2002
Posts: 134
Re: Rear leafs - what spring to use for good launch & good street manners

Jeff, I went through the same last year on my 70. I decided on three reasons
1.needed new springs
2.talked to a friend ( an auto body man ) he said that any new supports under these older cars will help hold them together and make other improvements. He also said I would need them to run with his 12.0s chevy
3. I wanted to go faster and straighter, so talked with calvert racing then bought their mono springs and bars.
Results after installing them: the car improved in ride, stance, performance, and smoked the 12.0s chevy. I have no complaints of using mono springs on the street!

1965 F100- 390,3 speed std. 270 compcam,411\'s
1970 Mach1- 408,AFR 205\'s,4 speed,411\'s
1999 Expedition 4.6 auto
2000 Mustang 3.8, 5 speed
+ other Fords
Bluemach170 is offline  
post #9 of 11 (permalink) Old 02-07-2008, 03:10 AM
Tech Contributor Gold
 
Join Date: Dec 2004
Location: Amish Wonderland Of Central PA
Posts: 4,908
Garage
Re: Rear leafs - what spring to use for good launch & good street manners

Of course you all know that this is a 2 year old thread and Jeffstar now runs in the low 11's??? Maybe he will come back and tell us what he did.

Old springs can work well with the Caltracs and some adjustable shocks (such as the Ranchos.) At least in my case, the 4 speed car did its best with a fairly soft suspension. I got fairly consistent low 1.60's (1.60 flat was best) after I swapped in the Mono-leafs (from 5 leafs) and set the Ranchos to "3." Automatics would probably use a stiffer setting.

I did try the 5 leaf springs before I bought the Mono-leafs and the car went nearly a tenth slower and the street ride was teeth chattering unless the shocks were set at "1" or "2". No thanks. At the track, this route might have been fine with other types of suspension improver's, such as slapper bars.

Dennis

65' Stang Street/Strip. Dart 434W NA, Victor heads, G101A 4 Spd, 4:56 rear gear, on 93 octane pushing 3550lbs. [email protected]

Last edited by dennis111; 02-07-2008 at 03:15 AM.
dennis111 is offline  
post #10 of 11 (permalink) Old 02-07-2008, 09:24 AM
Registered User
 
Join Date: Oct 2004
Location: Bethesda, MD
Posts: 1,564
Re: Rear leafs - what spring to use for good launch & good street manners

New stock rear springs, Shelby underride traction bars, KYB gas-a-just shocks, Global West subframe connectors and a rear sway bar. 60 foots in the mid 1.50s. Should 60 foot better this Spring with the increased boost.
blown68 is offline  
post #11 of 11 (permalink) Old 02-07-2008, 05:53 PM Thread Starter
Registered User
 
Join Date: Feb 2003
Posts: 1,211
Re: Rear leafs - what spring to use for good launch & good street manners

Good eye Dennis,

I went with a set of BOSS 302 leafs (re-arched 2 " higher). I bolted on my old Lakewood slapper bars after breaking the front bolt on one of the Shelby under-riders.

[quote=dennis111;1388915]Of course you all know that this is a 2 year old thread and Jeffstar now runs in the low 11's??? Maybe he will come back and tell us what he did.

408W, 10.x through the mufflers
slow-poke is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Ford Muscle Forums : Ford Muscle Cars Tech Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome