Leaf springs that handle, AND handle high power.

Well this has been ongoing ever since I went to a manual trans AND sticky 335 wide Toyos. The car REALLY sticks in a straight line either on the track or street and as a result is hell on leafs. I have Hotchkis springs in the rear and when I first put the car together with the 335's it had Mopar #415 oval track springs in it and after a few miles they ended up "S" shaped. Then I went to the Hotchkis springs when I went to the 6 spd BB package. Setting the pinion angle up with NO vibration, 2 degrees down from parallel, the driveshaft would hit the tunnel even in second gear. Tried a pinion snubber and it would act as a bump stop it was so close to the floor. Then I built some homemade Caltrac's and they worked well and my spring wrap problem was solved. Only down side to those was they took up the same realistate as the end links for my rear swaybar. I have since added 1.18" T-bars and a full 8 point rollcage and the ride is superb. I like the ride of the springs, but need to increase my roll stiffness with the rear bar. I don't have the money for custom springs so I have taken the bottom leafs out of my Mopar springs and cut them in 2 to make 2 half leafs, ala Mopar SS springs, to help these Hotchkis springs out so they don't end up "S" shaped. Here are some pics of where I am at, going to have to wait til tomorrow to get the proper center pins to finish.

Can't wait to hear how this goes!

Seems to me with 335/BB currently, you are knocking on the door of a complete redo with a torque arm or 3 link/watts set-up anyway and be done with it. I like and use leafs also, and I know all about costs, etc, but.....

I am going to have a doomsday back up plan lol!

Back together with swaybar back on. Will get a drive report later. Flipped my MeTracs around and they are on standby to go to Assassin bar mode if needed. Hellwig E body rear swaybar made to work with my relocated springs.

Shot of the spring with the half leafs.

Well it definitely helped a bunch. It can handle 2nd gear full power now. I am confident these will be good to go on the Road Course but will need the links at the AutoX or Drags. First gear goes into wrap,wheelhop, vibration slightly and is still not adequate. A torque arm would probably be the fix and still keep leafs, but a 3 link with watts and coilovers would'nt be that much more work. Now I say do I want to do that much work on my 8 3/4 or just go Dana or 9" too. The Gen III is a tad easier on the springs in the lower revs but its a whole different animal between gears, the powerband basically gained another 900 rpm over the BB.

Sounds like it is fixed for now. Another approach, very similar to what you did, is to run SS springs. There are several posts on this... I think best/recommended is two left hand springs.

If you get to the point where you can "hook" in first gear with your power level, I think the 8.75 will be toast in short order. I wouldn't spend any more money on the 8.75... D60 or beefed Ford 9".

It wants to wheelhop like crazy now. Looks like a built 9" and one of these might be in my distant future.....
https://www.cachassisworks.com/images/product/large/5857-u01-03_1_.jpg

Fancy! And Pricey!

Heres another more affordable option....
https://www.cachassisworks.com/p-1891-mustang-64-70-torque-arm-ii-33-length.aspx

GM guys have alot of cool stuff!

To my own experience, I would never have considered simple 4-leaf springpacks as 'handling springs'. Eventhough I'm seeing 1 thicker leaf surrounded by 3 'normal' thickness leafsprings.

Which such a nice upgrade at the front springsuspension, why keep playing around with just 4 leafs, or 4+2 halve fronts now?

I would look into either thicker, or just add more complete leafsprings, like 5 or 6 blades for handling purposes. Specially if you want to counter S-shaping and wheelhop better.

I also have hotchkis rear leafs and was wondering if they could handle future upgrade like that. Guess when the time comes, I'll have to upgrade to a different type of suspension.

sounds like a good plan except I like the current rate, and the ride is awesome. Ride quality is 80% what the REAR is doing in my experience. Pretty sure the wheelhop is coming from the rapid UN- wrap it has now. It was another failed experiment, oh well. If I can get this thing to put the power down it will be a rocket on an autox.

If you want to stop spring wrap up without increasing spring rate and keep it handling then something like CalTracs or Traction Master bars are in order

I think you're asking a lot of that 8 3/4.