[Cliff R]

Skip, I certainly hope they have full frames or at least sub-frame connectors and welded the axle tubes into the carriers if still using a GM 10 or 12 bolt diff........Cliff

[Richie Hoffman]

Tri city springs work great had them in mid 11 second cars they would 60 ft in the 140,s 10 second firebird on 10 inch slick I had went 140.
60 ft

[ponjohn]

I am going to run the Assassin bars on this build.

[Skip Fix]

Most of the Stocker guys use spools and I assume all the other tricks on the housing. Mine is plain Jane 8.5 81 TA 4 WD wth an Eaton 28 spline posi in it. I d have subframe connectors.

[Cliff R]

Without subframe connectors it is difficult to get one of these leaf spring cars to lift and not get all twisted out of shape.

Getting a leaf spring car to hook is more of a "recipe" than simply adding a set of bars, sticky tires and heading to the track.

My first 455 broke EVERYTHING behind the engine once I got the suspension dialed in and started hooking it really hard. So I ended up upgrading all the drivetrain parts until it was pretty much bulletproof, as outlined in my first response.......Cliff

[77 TRASHCAN]

Cliff, maybe some day you could span some pic's of your suspension pieces for us ( after snow season, LOL).

[Skip Fix]

Cliff I was pulling the wheels slightly when running the RAIV 400 and 12s(look at the avatar picture) and no twist with old Moroso subframe connectors, solid subframen bushings, solid stock car A arm bushings up front and the Tri Cities in the rear. There is a rear sway bar. Same deal when the car runs high 10s with the 455 and light wheels. Nothing rear trick and it is a T top car.

[Cliff R]

Skip, I was simply pointing out that sub-frame connectors are one of the first things we need to add before the rest of the suspension is going to work like it's supposed to. Once we tie the front half of the car to the back half, then other items can be added to help control pinion angle, axles twisting out of the carrier, springs wrapping up, etc.

At some point I'll take some pics of what I'm using and run a thread on them.

I personally like using an adjustable pinion snubber as holding the front of the carrier as it tries to come up thru the floorboard is a good place to start transferring weight and controlling the twist that the axles are putting on the center section.

An uncontrolled center section can result in "wheel-hop" and parts breakage as well as the tires load and unload on the track as they loose traction.

4 link set-ups are much better, at least without nearly as much effort as getting these leaf spring cars to hook. To start with those cars have full frames under them, so we don't have nearly the chassis flex to deal with as the car lifts and transfers weight to the rear tires........Cliff

[Formulajones]

We have both here. The factory 4 link stuff is a more simple deal. They don't move around as much, easier to control. They just don't take too much effort to make them work well.

Leafs are a different deal, They rotate more, so more care is needed to control pinion angle. I like the pinion snubbers for the sneaky approach, and used along with angle plates to get pinion angle where it needs to be. The "Day 2" movement has gained steam in recent years, to the point that vintage traction devices added are very well accepted among the car crowd, even on high dollar muscle cars now. Also works well if setup properly.

I've done the leaf spring clamp deal with mixed results. My Firebird didn't like it actually. Would 60 foot about the same but was very inconsistent. It stiffened the back of the car to the point that it hurt weight transfer. This particular car just likes softer action in the rear with some squat. Wheel hop has never been a problem with it. So the pinion snubber deal in the rear was all that was needed, most of the other tricks were in the front. 2 of my leaf spring cars can't go the aftermarket leaf spring route for various reasons so takes a little more effort to find what works.

Every car seems to be a little different but everything outlined in this thread so far should get any leaf car hooking with either approach you take.

[ta man]

I'm currently running basically a stock suspension. I do have have bolt in CE frame connectors that are welded at the front and solid subframe bushings. 3 way CE shocks, factory front control arms,leaf springs are slightly stiffer than stock.The car will 60 ft in the 1.56 to 1.61 range but needs a good burnout leaves level and smooth.
I also like the stock suspension look, plans for this year are to loosen the front end and add the leaf spring clamps and adjustable pinion snubber I've had laying around finally.

[ponjohn]

Originally Posted by ta man

I'm currently running basically a stock suspension. I do have have bolt in CE frame connectors that are welded at the front and solid subframe bushings. 3 way CE shocks, factory front control arms,leaf springs are slightly stiffer than stock.The car will 60 ft in the 1.56 to 1.61 range but needs a good burnout leaves level and smooth.
I also like the stock suspension look, plans for this year are to loosen the front end and add the leaf spring clamps and adjustable pinion snubber I've had laying around finally.

Sounds like the Stock Eliminator guys like the Global West stuff for "looseness" in the front end.

[Skip Fix]

Cliff you are right stock stuff just won't cut it when you start adding HP. Heck I can remember riding in my best friend in high schools 73 Z28 stick car and feeling the rear end wrapping and hitting the stock pinion snubber! And that was not a high HP car.

[Half-Inch Stud]

I has used Lakewood's "J-bolt Slap bars" with 5- leaf stiff stack for great Reliability and success.
Wonder how they rank these days?

[Formulajones]

Originally Posted by Half-Inch Stud

I has used Lakewood's "J-bolt Slap bars" with 5- leaf stiff stack for great Reliability and success.
Wonder how they rank these days?

Still used and effective. That was pretty much the "go to" setup during the 60's and early 70's stock and super stock days.
There are things you can do like preloading, adjusting snubbers, extending the length so they hit the spring eye and not the spring itself. Easy to do with smaller square bare that slides inside, weld, redrill for snubber. Rarely have I seen a slapper bar long enough out of the box.

Grumpy modified his. Pretty much all he used during his hey day running the F-bodies. I have a pair similar to these on another car. They work!!!

[vitamin c]

With the rubber pads top and bottom on the leaf spring cars, how are you guys adjusting pinion angles? Better yet, are there ways to eliminate the rubber pads all together? I dont see the rubber spring insulators helping much as far as 60' times, axle wrap, or wheel hop, goes

[Formulajones]

These..... https://www.summitracing.com/search/...ngle/4-degrees

They usually come in different degrees and widths. I also sometimes use them on the traction bars too, to get the bars up parallel with the spring not only for more ground clearance but also to avoid the need to shim the snubbers up.
Then I can trim the snubber to exactly what I'm looking for.

[Formulas]

Polyurethane leaf spring mount pads have to help a touch with wrap up and movement, I recently installed a set on one of my birds and while its still on the fast idle cam at cold start up it now chirps the tires in the garage going into drive and reverse, didnt do that before,
So im getting more transfer of power vrs absorbtion

[Cliff R]

Everything with a leaf spring car starts when you tie the frame together. I also remove the back seat and extend the front leaf spring perch bolts up thru and back them with big fender washers as they pull easily out of the wimpy stock nuts the factory used.

I also "box" and weld the front of the sub-frame connectors vs drilling and bolting them in place.

Next step is to weld the axle tubes to the carrier as the factory just used a couple of "spot" welds and we've seen enough of those crack and break to not even attempt this deal w/o welding them first.

Adding an adjustable pinion snubber comes next, then all that is really left is to move out to the leaf springs and maybe add drag shocks.

Factory leaf springs need harder or solid bushings put in them in addition to clamping the front sections. I much prefer buying leaf springs made for drag racing.

I suppose a guy could add some sort of traction bars at this point, but I don't like the look and don't like to "advertise" when I'm racing at the track.

One thing I've ran into with this deal that I didn't mention is that the wimpy factory bolt that comes up thru the center of the leaf springs needs to be replaced with at least a 7/16" hardened bolt, so drill and install that before proceeding as "working" the springs with perfect traction tries to separate all the spring sections and shears off the bolt that holds them together and locates them as well.

I would also recommend checking the welds between the spring perches and axle tubes. After all the mods to my diff I ripped them off the axle tubes due to poor factory welds.

Other options at this point are to upgrade from the factory posi carrier to something stronger. The "S" type posi units are pretty strong, but the spider gears don't have nearly the contact patch as aftermarket units like the Eaton, and the gears are "brittle". I exploded two of them in less than a dozen runs once I started hooking solid and running really quick 60' times. Mosier axles with C-Clip elim's are also a good idea, but the bearings aren't as good as the factory set-up so keep an eye on them if you are putting a lot of street miles on the vehicle.

Last thing to mention is that for the cost of upgrading a factory 8.5 diff (for example) will cost close to or just as much as replacing it with something much better, especially if you are paying someone to do all the work.......Cliff

[HWYSTR455]

I agree with those who mentioned the 2nd leaf going up to the front mount bolt/point, like the original Rancho GT III springs (modified military wrap). It 'acts' like a slapper. The Ranchos would actually have a half-wrap around spring eye, but it's been proven that it's not required. Most just make the 1st leaf (one with the eyes) thicker now.

The original Herb Adams mod of raising the front eye location by an inch is still valid, improves anti-squat, which improves bite and corner exit traction.

I agree with Cliff on the locating bolt too, stepping up one size and replacing is good practice. Depending on the type of perches, on a multi-leaf, a hard launch can break or make the locator slip out of the perch.

If you're ordering a new rear, the hot ticket is to use mono leaf perches with multi leafs, and eliminate the top pad. That way you can have the locator pin actually pass through the perch, for a more positive retention/locator.

Also agree with using better hardware for the front mount, I've seen those come apart.

True too on once you tie the frame in, and making sure the area it connects to in the rear boxed/braced. For that matter, once you tie it in, you're better off going to solid body bushings too.

Clamp thing never worked for me, in a number of areas of performance. Not to mention it just plain looks tacky. The leafs have to slide, it's part of their' function (of articulation). If they are old, and are 'glued' together, that's part of the problem, you need to just replace them. You can take them apart and make it so they move freely again, but for the effort, your better off just getting new ones. Some leaf manufacturers even use thin sheets of Teflon or plastic between the leafs to help articulation/slide, but those over time wear out, and create slop between the springs.

Shocks too are a biggie when it comes to wrap/hop. In drag racing, some swear that you want a worn out shock, but that is just adding to the problem.

There's nothing wrong with leaf setups, and with solid bushings, locate the rear very well, better than some 4 links. With a leaf setup, they are less likely to bind, especially when compared to OE 4 links. With slappers or sliders, you can actually adjust the amount of squat/loading, better than with just a pinion snubber.

IMO, unless you are dedicated to drag racing, slappers or sliders are not needed, it negatively impacts daily street driving, not to mention loss of ground clearance. It sucks when those things hang on a speed bump, or entering a parking lot. It's generally better to correct any traction problems with better leafs.

.

[Formulajones]

Originally Posted by HWYSTR455

With slappers or sliders, you can actually adjust the amount of squat/loading, better than with just a pinion snubber.

IMO, unless you are dedicated to drag racing, slappers or sliders are not needed, it negatively impacts daily street driving, not to mention loss of ground clearance. It sucks when those things hang on a speed bump, or entering a parking lot. It's generally better to correct any traction problems with better leafs.

.

Correct, I preload the passenger side slightly more with a slapper bar (tighter clearance) If done right the car will launch straight and true every time.
You can accomplish the same affect with just the pinion snubber buy adding a leaf to the passenger side. Some of the drag leaf springs may already have this method incorporated into their design.

Slappers are fine on the street. We daily drive them without issue and we have some pretty nasty speed bumps and parking lot entrances around here. It helps tremendously if you shim them like I mentioned earlier. They are tucked up parallel with the springs on my cars, and as long as your running a typical 27-28" tire, the bars aren't even close to the ground, no closer than a front lower control arm. If you run a short tire, like a big wheel short sidewall type of deal, then I could see that being an issue. But with a normal tire, I've never once had the bars hit anything, but in case they ever do, that's why they have an angle cut in the front.