This is the intersection of a verticle line through the front wheels, and the center of gravity horizontal line. Correct? So then the intersection of the instant center (line through the tire contact patch and the front, in my case, ladder bar mount) and the neutral line, determines if the car will squat or rise on the hit, right?

It would be a line from the rear tire center of the contact point to the height of the Cg at the front axle. In your case fairly high. What's cooking?

I've seen it explained 2 ways. Line from the rear tire contact patch through the C/G height above the spindle. And line from the rear the contact patch through the Cars actual C/G. I believe in the cars actual C/G as being the correct line. The location of the front attachment of the rear suspension will cause the chassis to try and rotate around the C/G clockwise or counter clockwise depending on whether that location is above or below the line. As the car moves forward the force at the suspension locating point is in a constant state of change. On a single attachment,(leave spring/ladder bar) it starts upward and transcends to forward. On a 4 link car the upper bar is pulled back and the lower bar is pushed forward creating upward lift in the theoretical pivot intersection of the 2 bars. The hit (which the axle housing always extends from the body) is controlled by the shock. The load/traction after the hit can be adjusted by bar location, more/less power, weight distribution. What happens after the hit depends on whether there is enough traction and power. Depending on the variables after the hit the car will do a combination of four things. Move up, down, forward, or spin the tires.
Doug
When I'm incorrect I'd like to admit it. The neutral line is definitely through the C/G-front spindle point. I believe all the rest of my information here is correct.
Doug

One thing to clarify is that the tire ALWAYS goes down on the hit. The anti squat % controls what the body does after the hit.

And the transition from hit to the effect of the instant center on the chassis rotation is extremely short, but still has a big effect. It would be interesting to know how much difference there is on that time for different performance cars. On my car, I see it happening in less than one frame of video.
Leigh, if there is enough traction to stick the tire with a low front mount hole, the car will pitch rotate nose up, and have more momentum to go into a wheelstand. Above the IC for a very short instant it will pull the nose down, but is hitting the tire harder at the hit. So there is a loss of energy for raising the front end into a wheelstand. Most of us are crutching something that isn't optimum, like Cg location, IC length of location, weight distribution, or lack of power. My car would do better if I had more weight concentrated in the middle, with a lower Cg and a fourlink so I could move that IC more.

I like pictures, attached.

I am lazy this am so here is something you can read. Some excerpts from Bickle

http://www.onallcylinders.com/2015/04/23...pension-system/

I don't ignore it, but IC and AS are my secondary considerations. I mostly use that information just to compare one location to another. It's not wrong to do, but if you decide you need to have an IC and AS location in a specific location, you have to pay attention to where the bars are, as you can end up with some funky bar locations trying to achieve it.

The geometry of the 4-link is my primary concern. Top and bottom bar angles, bolt spread and height front and rear, top and bottom rear bolt location in relation to the axle centerline, etc. The physical geometry and locations of the 4-link attachment points are what determine the reaction part of "For every action, there is an equal and opposite reaction".

Length and height play a BIG part in the way the rear
suspension acts... as well as the rear attachment points
on the housing... the farther apart the rear points are
it tends to wheel stand... this hold even more so on a
smaller wheel base car... I own every book there is on
ladder bar and 4 link and I like to read them ALOT.. I can
make my car(as well as others) stand up or keep the front 4"
off the ground... the shocks also play into this but if the
4 -link is set a certain way.. the shocks wont need the big
control(less body separation)

I've also read a lot of the information published out there, but usually come away disappointed that much of it is pretty basic. And some of it is dated as people continue to figure things out. However, I don't blame people like Bickel, Jones and others for not giving away the farm. These are not the only places to get information and the benefit of experience. Physics controls much of this, but opinions on how to do it vary a great deal. I'm willing to listen to all of them objectively.

The more I deal with this stuff, the more important that I see the shocks being in the big picture. Anyone who does a 4-link and doesn't put good double adjustable shocks on it, has wasted their money.

Well I guess I have wasted my time.. I run a single adjustable
rear shock from days of old.. 12 way adjustable QA-1s... but
I only run a 1.19 60'... I set the IC height about 1" above
the anti squat...I do vary the length based on the track but
usually not more that 10"...if you set the 4-link above the
back will tend to rise(depending on length) and if its on the anti
squat you wont need the double shocks... this is from MONTHS of
testing.. both on my ride and other costumers that I take care of
their cars... each one of these cars I built the chassis and set
up the balance
EDIT
I can set the lift like this (nice for pics) OR like this
I dont like to run this pic since I didnt buy it

Sorry Mike..........but a 1.19 60ft for that car is dead slow. I don't care where you move the bars, you can't "fix" junk shocks.

Not sure what Leigh is asking in regards to his car, but a ladder bar car is never going to squat........the instant center is too short

That is probably true over 99 percent of the time, but my videos say mine can. Here's how to do it. Set the engine back too far, set it a bit too high, then shorten the wheelbase six inches, and put a front ladder bar mount on it with the lowest hole at five inch or less off the ground. Then it can get below the neutral line, and your chassis can do some strange things if you get lost on adjutments, like roll rotate so severely you think it is going to twist the ladder bars permanently!

Well I disagree with the 1.19 being slow... how many on
this board are near it.. its not one of your BIG engines.
its a 400 N/A.. I dont call my old QA-1s junk.. sure I dont
pay $1000 for a shock.. but it hooks GREAT... maybe its
not YOUR caliber equipment... but it works GREAT for me...
I have never been a engine builder but I can build a light chassis
which I prefer to do anyways

I'd take that 1.19 60 ft and be proud of it And I have run 8.70s

The last few times out I run 8.90s... I put the car away
since then... but I guess 1.19 is crap according to Monte...
oh I did do a 1.18 once... but I never count the best.. just
the averages

I wonder what Leigh is looking for?

Sorry, was out of town. While not a chassis expert, I have experimented with this ladder bar setup a fair amount, and it always boils down to liking a high cg. Lot's of travel, limited travel, loose shock, tighter shock (Afco single front, .810 t/bar, Afco doubles rear, 130lb coil springs), lower the car and it spins. Raise the entire car, until it mimicks a 002/003 SS spring ride height, and boom, it's there. 3150 race ready, 50/50 weight, 6200 flash, 4.56 cog, 535 ft lbs@5300. Ladder bars have been tried in all positions, with air pressure adjustments from 8-14, from 11.5-29.5-15 Phoenix, to 10.5-29.5-15 Hoosier. Both like 9. Doesn't matter what track, either. It is what it is, I simply got extremely tired of messing with it, but alway's promised, I'd force myself to positively learn WHY. Thanks everybody, for the helpful info.

It's not about what others do.......it's about your car. That's a light weight, tube chassis car with a 4-link that has enough power to run in the 8s. And you can say whatever you want, but those QA-1s are NOT a race shock especially for a 4-link car. Never have been and never will. A properly set up 4 link car NEEDS doubles because of the actions the housing takes and you need adjustments to control those actions, not one knob does both.

And I wasn't saying you needed $1000 shocks........I was saying you needed BETTER shocks, as in doubles.

To be honest Monte.. I really dont give a crap what you say about
my ride.. 620hp ... you think its crap... to FREAKING BAD... it runs
8.90