2nd gen leaf spring suspension for drag racing
 

I’m in the process of upgrading my entire rear suspension on my 1970 Trans Am. I’m curious as to what is considered to be the go-to competitive leaf spring suspension set-up these days? My TA has been mid 1.4X 60’ times with air shocks and old school south side machine lift bars on a 30x12.5x15 ET Street bias-ply tire.

484” IA2 with as cast highports (around 660hp), T400, 12 bolt 3.90 gear, 10 point cage

In front I have completely updated the suspension with CPP tubular control arms, Viking hybrid double adjustable coil overs (7081COK-2A450), proforged steering rebuild kit, and I’ve added CPP hydrostop brakes, Borgeson steering box, and remote power steering to make street driving a bit more enjoyable.

So far I have Calvert split mono-leaf springs (#230-43) and I’m considering an anti-roll bar set-up and Viking double adjustable shocks.

What are the fast guys running?

I don't consider us fast but I would recommend the anti-roll bar. Split-mono's and Calvert bars are the hot set up along with the best shocks the budget allows.

Calvert bars


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Calvert split monos, Caltracs with as much shock as your budget or needs allow....I'm running the basic Calvert shock in rear works for my car.

I meant to say CALTRACS.

https://calvertracing.com/product-categories/caltracs/

A interesting tid bit for conversation. The Calvert split mono would more often than not be a good choice if you are using their bars. It probably doesn't apply here but in a heavy car some go with a multi leaf spring.
Many years ago John Calvert was working closely with Landrum spring company, this before the introduction of their split mono spring, and they recommended a 300 rate spring on my car back then.
This was before their split mono spring and today I believe they would not recommend one that is that that stiff.

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I use the 300 rate multi-leaf spring in my red 74 Bird. They work well.

" I believe they would not recommend one that is that that stiff."

I might want to retract that statement regarding the use of a higher rate spring.
Sorry, that was something I presumed since reading over the years about their SPLIT MONO LEAFSPRINGS and MONO LEAFSPRINGS that are lighter.

Agree with Paul the 300 rate springs work well. I've had a 1.43 60-ft with the Landrum springs and the Caltracs bars.


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Sent u a pm

Thanks for the input guys. I’ve decided to go with the full 70-74 set-up from Funkhouser Race Cars https://www.funkhouserracecars.com/

70-74 Antiroll bars and shock relocation kit https://www.funkhouserracecars.com/p...hock-mount-kit
70-74 Leaf spring sliders https://www.funkhouserracecars.com/p...-spring-slider
70-74 Traction bar set-up (like CalTracs but larger diameter)
Longer Viking double-Adjustable shocks
Tie-down brackets

Example:
http://lstwo.com/images/39205007986961152524.jpeg
http://lstwo.com/images/26718039877609474609.jpeg

Leaf spring sliders are a good idea.

Back in the day Tri City "Launcher Springs" were GM copies of the Mopar Super Stock springs and the choice of most of the NHRA Stockers before Cal Tracs came out. My 78 TA 6o ft'd 1.51s it he them with a 10.90 time slip. I had a small 5/8" factory rear sway bar on it. They worked really good but were stiff and heavy.

The IA Camaro has Split Leaf and Cal Trac bars. Factory rear bar was too close to the 12 bolt's rear cover/brace so I used a Second Gen Pro Touring rear bar with a little longer "legs".

Not as fast yet as some of these other guys .

That looks really nice.

Do you have any pics of the car off the lift?

Thanks

I went with Funkhouser set up, but am still currently under construction. The product itself though is absolutely top notch, and customer service every bit as solid. You won’t be disappointed with his quality.

I'll be posting pictures of my car as it is being completed. Right now they are working on the front suspension/steering and are making a remote power steering adapter bracket so I can still have power steering when using the Stainless Headers turbo manifolds. My All Star remote power steering pump will be on the driver's side head and the alternator has been relocated to the passenger side.

Yeah they are great guys. I'll let them know about the positive feedback. My TA is physically in their shop getting the work done now. Don't be surprised if we have a few extra Pontiac specific parts available from them after my car is done. One for sure will be the remote power steering adapter plate.

That is awesome! Can’t wait to see how it turns out, and what you guys come up with!

Small update…

• Calvert springs are in along with new spring perches are in

• Funkhouser shock relocation kit is fitted and looks awesome.

• Shocks are Viking Crusader (red eye) double adjustable and are longer than stock for additional shock travel and tuning.

• Tie down brackets added

• Funkhouser roller bearing sliders are in. These are very cool pieces.

• Funkhouser custom low profile front rocker bracket

• Funkhouser HD lower bars with HD rod ends

I’m not doing the anti-roll bar at this time. I street drive it and hope to autocross one day. Also, the trunk pan had seen better days so we replaced it while everything was out :cool2:

Nice work!

These lower brackets are pretty slick. Tons of adjustment available in them plus it’s a tie down and relocates the shock.

http://lstwo.com/images/50932630540417724616.jpeg

Nice piece's there.

GT