I'm looking for front end alignment specs for a 70 SS LS6. Caster, Camber, Toe I've searched the web to no avail. Hope someone can help.

For 1970 Chevelle, Monte Carlo and 116" W.B. Wagons

Caster:
SS, El Camino, Monte Carlo: Neg. 1/2* plus or minus 1/2*
All others: Neg. 1* plus or minus 1/2*

Camber: Pos. 1/2* plus or minus 1/2*

Toe-In (Total): 1/8"-1/4"

Neg. caster will make the car not track very well, it will wander instead of going straight.
Pos. camber will not be very good either.
A good mild street alingment is 1/8 deg. neg camber. 1/8" total toe in. Caster manual steer 2 deg pos. power steering 3-4 deg pos. The caster should have 1/2 deg less on the left. (example left 1.5 deg. pos. right 2 deg pos)

Glenn those spec have got to be from the service manual, slo307 is right you will end up with a poor handling car. The alignment specs for todays tires would be like what slo307 gives. Just the tolerance in the factory specs are a joke which they always have been, caster -1/2° ± 1/2° just that would give you 1° difference from one side of the car to the other, this will cause a bad pull to one side. As to camber 1/2° ± 1/2° tolerance here could put the front tires at 0° on one side and 1° on the other, you will be buy tires by the gross. Tolerance for alignment should be no more than 1/8° for caster and camber, and 1/16 inch on toe setting. Go with slo307 alignment specs and the tolerance I gave you will have a great handling car on todays tires and they will last for years.

Yep, they came right out of the Service Manual. I figured it'd be a reliable source, but I didn't give any consideration to changes in tires. I thought 1/8"-1/4" toe-in was a extreme, but I don't know much about front end specs.

I guess the 1/2* less caster on the left that Slo307 mentioned is to compensate for the driver not being in the car. Why the big difference in caster for PS and manual steering?

I have an H-O suspension on my car and their recommended specs are:
Caster +3 1/2*
Camber -1/2*
Toe-in 1/8"

That's pretty much in line with what you guys said, but I thought it was due to the different spindles and lower springs.

Thanks for the explanations.

Staggering caster is to counter the effect of the crown in the road. The center of most roads are crowned so the water will drain. A manual steer car is much harder to turn the steering wheel. By adding pos. caster the car will track on the hiway better, but the steering effort increases.

I searched around this morning and found something that said "the car will pull to the side with less caster", so that makes sence, because that will help it pull to the left uphill towards the crown in the road.

Is that a factory way of setting caster, or is it something that people do to get easier steering?

slo307 that set is for all chevelles right? 1966, i also did the tall spindle swap + GW arms - the GW site says up to 5 caster? is that to much? what will too much caster do

Those specs will work on all a bodies, or any rear drive car for that matter. GW says + 5° due to the fact their upper arms give you the ablity to get 5°, but with the stock spindles and control arms 3.5° is about all you can get out of the front suspension.

The more pos caster you can dial in the better the car will track down the hiway. For auto crossing you would not want to excede about the 3 pos range because it will not turn in as well with 5 pos. On a Land Speed type car you would want to set the front up with 9+ pos because you want the car to go straight. You can not get that much caster in an a-body unless you build the car around it

Thanks a lot. I'd forgotten what little I used to know about front end alignment. It helps to have an idea of how the different specs affect handling.

I've been thinking about making some angle measuring tools - nothing fancy, for camber I was going to cut a straight 1x2 16 3/8" long with a set screw in one end. Then figure the distance the screw would have to be backed out to put it at 1/8* in relation to the 1x2. I think if the 1x2 is plumb and on the bottom wheel flange, and if the set screw is on the upper wheel flange, that should indicate the the wheel is leaning in at the top at 1/8*. I guess all the tires should be level with each other too.

I'm not sure about the caster guage. That'll take some thought.

Is the caster angle made of these two lines?:
1) the line drawn through the ball joints
2) a plumb vertical line

Does positive caster mean that the top ball joint is behind the lower ball joint in relation to vertical?

Glenn,

Yes, positive caster means that the upper ball joint is "behind" the lower ball joint when viewed vertically. The measurement of caster using the left wheel as an example involves turning the wheels to the left 15* and setting your gauge to "zero". Now turn the wheels to the right 15* (30* included) and check your gauge. This is the process that I was told to use with the alignment gauge that I bought from Pole Position.

Good Luck!!

Daryl

Thanks Daryl. I've been trying to visualize what's happening with this stuff and it seems like abstract math.

I think I understand the part about turning the wheels 15* each way and checking for 0 caster, but I'm having trouble understanding how that 15* would apply to all caster settings. Maybe the gauge is made in such a way where you set it to a specified angle, and then adjust the shims to end up with 0* and the 15* turns?