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Suspension Choice

crahill39

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Hello - I need some input from all of you experienced racers. I am building out a 71 GTX that will be split 50/50 street & strip. The 440 is at the race shop being built with the intention of seeing some strip time and hopefully get in to the 12's. My question is about rear suspension choice. I was looking at the RMS street-lynx setup vs. leaf spring / caltrac setup vs. a true weld in 4 link setup. I am trying to stay on a budget and wanted input if spending the $$$ on the RMS or 4 link setup is worth it for a car that see limited strip time. I am at the point where I have to make a decision fairly quick and would like to hear some thoughts from you guys.

Thanks,

Craig
 
I've seen plenty of B bodies running sub-12's with HD leaf springs and pinion snubber; or you can run Caltracs. Subframe connectors and torque boxes should be on the list too.
 
You dont need to spend the money. I was running 11.2 with worn out stock leaf springs in my GTX.
 
If you really want them, sounds more like, not necessarily need them

You can go a different route & do tubular UC arms now
do a set of tubular LC arms later, than add a tubular K-member
latter down the road too, if budget is a big dictator...

I did the QA1 route for front suspension, with SPC double adj. UCA
both products are at great price point & can do a bit at a time if need be,
albeit I purchased all at the same time...
I've used the old Capps Automotive stuff a couple times in the past
{QA1 bought the out, pretty much same product}
Had great luck & success with them too, basically bolt in too,
easy peasy, there are far more stuff out there to chose from,
check out different mfgrs stuff...

RMS or even Magnum Force Racing stuff is nice too,
but it's a big hit at once too, more pricey, but nice if you can swing it...

Ride-tech has some decent rear suspension stuff also,
basically bolt in & affordable for the most part...

So does Magnum force racing...

CalTracs is a great option, unless your going fast enough
to justify a real coil-over & ladderbar or real racing 4 link set-up...
I've been in the 8's on CalTracs

You shocks are a very important part of the ultimate selection too
S/S leaf springs are a decent choice for the budget minded too...

IMO for a 50/50 street car, you don't need the most expensive stuff either
especially to run in the 12's, basically a moderately modified OE suspension
can easily do that too...

Trick parts look nice & weight less, far more adjustable,
ride height, center of gravity, weight per wheel etc.
but from what your looking to do,may be better spending the money on other parts,
they're not necessary, to run 12's

I'd say lighten up the car, it's far easier to run fast with a lighter car...
It's all about HP to weight ratios, more rotating mass/weight kills ET too...

Do a bit at a time front suspension now & rear later, visa versa etc...

Lots of companies to chose from, just do your research, due diligence...
 
If you must, call Carl Gerst.
He can make anything you want.

20160715_160109.jpg 20160715_155939.jpg 20160715_155926.jpg 20160715_155917.jpg
 
Unless you want to spend money for "cool-guy" stuff....stick with the stock front-end, and I'd personally use the WHOLE Cal-trac setup in the rear. I just had S/S springs in my one car, and it pulled the front-end on the street. Pumpgas/hydraulic flat tappet motor.
 
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I've seen plenty of B bodies running sub-12's with HD leaf springs and pinion snubber; or you can run Caltracs. Subframe connectors and torque boxes should be on the list too.

x2
 
The GTX had the torque boxes from the factory (upgraded the front ones), but I still need to choose the subframe connectors. My budget is pretty tight as I put most of it into the body and motor. I was planning on breaking down the old leaf springs this weekend, but all these comments have me thinking the Caltrac option is the best route along with a slow upgrade of the front to the QA1 setup. Thanks for all the input. You guys are awesome. Here are a couple pics of
the GTX in paint !!

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For Ultimate Traction...Cal Tracs are the only way to go. Must have complete setup to be effective.....Cal Trac Bars, Cal Trac Mono Leafs, Cal Trac 9 Way ADJ RR shocks, Cal Trac 90/10 front shocks and 5" of free front end travel...DO ALL THIS AND THEY WORK.
 
For Ultimate Traction...Cal Tracs are the only way to go. Must have complete setup to be effective.....Cal Trac Bars, Cal Trac Mono Leafs, Cal Trac 9 Way ADJ RR shocks, Cal Trac 90/10 front shocks and 5" of free front end travel...DO ALL THIS AND THEY WORK.

I am pretty new to this, so could you explain what you mean by 5" of free front end travel?
 
US CarTool has good subframe connectors; I have them in my Coronet. They're weld-on, nice fit. Because of the age of our cars you'll probably need to still trim them some. While you're car is on the rotisserie is the perfect time to install 'em. The downside, under carriage will need to be touched up.
BTW, the car looks great; love the color.
 
US CarTool has good subframe connectors; I have them in my Coronet. They're weld-on, nice fit. Because of the age of our cars you'll probably need to still trim them some. While you're car is on the rotisserie is the perfect time to install 'em. The downside, under carriage will need to be touched up.
BTW, the car looks great; love the color.

I thought about buying them, but opted not to at the time. I could still add them as the undercarriage is not painted and is going to be coated in Raptor liner instead. I was also looking at the bolt on version from Unlawful racing.
 
I am pretty new to this, so could you explain what you mean by 5" of free front end travel?
Front End Free Travel is:
1) Put a yardstick up to the edge of your front fender wheel well lip.
2) Let say it measures 32" from the ground up to the bottom of that lip.
3) Put a floor jack under your K-member and Jack the car up until the front tire lifts off the ground.
4) Now measure to the bottom of the wheel well lip again.
5) If the lip now measures 37" your car came up 5" before the tire came off the ground then you have 5" of free travel.
6) Your front end joints need to be in good shape to move freely...I rebuilt my front end with all new ball joints, etc.
7) Cal Trac Tech wants the front end to move UP 5" immediately when you launch the car to start the start the motion.
7a) I had about 3.5 inches but then I unscrewed my torsion bars and let them "sag down" a couple inches.... Then I had my 5 inches of free travel.
8) Your rear leaf spring shackles should be free to move easily also.
9) Cal Trac Tech wants you to have 2 guys to be able to start pushing up and down on the rear of each rear fender and actually almost be able to start "bouncing" the rear of the car up and down like a basket ball...this is WITHOUT THE RR SHOCK INSTALLED.
10) I set my bars at the recommended setting in the installation booklet...and set the RR 9 way Adj shocks at 9 which is the stiffist setting, like Cal Trac Tech said.
11) I did all of this and first time out when I launched it pulled both front wheel off the ground about 6" for about 6 or 8 feet out...just perfect
 
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Front End Free Travel is:
1) Put a yardstick up to the edge of your front fender wheel well lip.
2) Let say it measures 32" from the ground up to the bottom of that lip.
3) Put a floor jack under your K-member and Jack the car up until the front tire lifts off the ground.
4) Now measure to the bottom of the wheel well lip again.
5) If the lip now measures 37" your car came up 5" before the tire came off the ground then you have 5" of free travel.
6) Your front end joints need to be in good shape to move freely...I rebuilt my front end with all new ball joints, etc.
7) Cal Trac Tech wants the front end to move UP 5" immediately when you launch the car to start the start the motion.
7a) I had about 3.5 inches but then I unscrewed my torsion bars and let them "sag down" a couple inches.... Then I had my 5 inches of free travel.
8) Your rear leaf spring shackles should be free to move easily also.
9) Cal Trac Tech wants you to have 2 guys to be able to start pushing up and down on the rear of each rear fender and actually almost be able to start "bouncing" the rear of the car up and down like a basket ball...this is WITHOUT THE RR SHOCK INSTALLED.
10) I did all of this and first time out when I launched it pulled both front wheel off the ground about 6" for about 6 or 8 feet out...just perfect

Thanks so much for the explanation!
 
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