Weight transfer for stock suspensions

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   So... no, since the six and the eight engines are not much different in total weight, and since the free height of the springs is probably the same, and since the shock extension is the same, I'm not going to say "It's all about spring rate".

I will say 'It's all about center of gravity' though, as I understand it.

And this is an area where an AMC car can really 'shine' because some models came with torque link traction bars (keeping the commentary on track with AMX and Javelin cars, avoiding the torque tube cars)

1) You can't get the front end to rise if you don't have enough 'bite' (if you have too much wheelspin)

(it really doesn't make any sense that AMC would put longer springs in the six cars; that would be 'deep coil' design... but all pre-'70 strut type front suspensions were a 'deep coil' design (regardless of engine) ...and all '70-up cars were a two ball joint 'short coil' design ~whatever, they are two different designs which were engineered for long or short coils... short coils are cheaper to make; faster to wind fewer coils and contain less metal to reduce costs)

2) The way to get more bite is by attempting to adjust what is called 'instant center'.

-Instant center is an invisible place somewhere between the drive wheels and the car's center of gravity.

The instant center is also called the car's 'reaction point'.

The reaction point is/should be somewhere close to the car's center of gravity.

That distance, how close or how far away, is leverage afforded by the geometry.

The location of the instant center or reaction point applies leverage upon the car's center of gravity.

Study it: Google it; 'reaction point' and/or 'instant center'

...even most of those guys trying to explain it don't absolutely know everything there is to it... (like me, I have my theories too, up for debate)

Depending on where the reaction point is, this can make the front end rise or fall, the rear end rise or fall, even cause the whole chassis to twist when load is applied.

The torque link cars are designed to slightly rise in the rear when acceleration load is applied and slightly drop in the rear when the brakes are applied: both done attempting to keep the car level and 'stable' under all operating conditions IE 'sports car' conditions.

(the torque tube cars force the whole chassis to rise when powerbraking the vehicle, slightly more in the rear than the front, but the whole car will rise higher because the leverage from the rear axle is pushing very close to, but slightly behind the car's actual center of gravity, and since the car cannot roll (powerbraking it) it will move up instead)

Intentionally avoided mention of rear left spring: yes that side 'lifts' by 
torque reaction in the axle and needs a strong spring anyway.

(the Dodge Ramcharger engineer's website discussed that aspect as well; chassis twist, and pointed out how to install a single traction arm on the right side of the rear axle to the frame of the car (this would be like taking both AMX torque links off and installing one large torque link on the passenger side)

But the major wheelspin is well known to occur on the right rear tire.

ON A street stock drag race AMX THOUGH...

One might try 'staggering' the torque link preload adjustment, to see how that affects 'bite' (that'll strain the rear axle housing)

One could try staggering leaf spring pinion angle shims...

One might try taking one torque link off... maybe the driver side link/maybe the passenger side? (not recommending this for any street car, because this affects the brake load input to the frame as well as acceleration load)

One could try using pinion angle shims: pinion yoke pointed down is more bite, pointed up is less bite (this has to do with 'calculating torque of an angle' -study in physics)

One could try devising offset torque link bushings, to change the angle of the torque link arms, from the axle to the chassis: this will definitely change the car's 'reaction point' in relation to the center of gravity.

If you could get away with it, you could try moving the upper torque link locations down, or move the front link locations up, to make the links more parallel with the leaf springs. -this will move the reaction point higher to pull down the chassis in the rear... too much and it can pull the axle up and lose traction by lifting the drive wheels...