Ok I will try to give you a sense of what caster does. 4-vettes quote above gave a perfect version of what it felt like on the highway with more caster, less "sensitive" more "stable". But yes his 77 does have PS, and he was running 2.75 degrees caster before, he increased it now, but I do not know the number. Let's guess he has somewhere between 4 & 6.

When the caster is set positive, the upper ball joint moves rearward about 1/4". That is the reason for the large shim stack on the rear stud, vs the front. I have heard factory cars can usually go up to around 2.75 with stock parts. GMs manual steer specs call for around 1. PS around 2.5

The rearward tilt on the balljoint axis means the R Fr spindle moves downward on a Right turn. The opposite effect on the left side. A left turn moves the spindle down. This has the effect f the driver trying to push the tire down when he turns, or actually lift the car slightly. So the overall effect looks like a "frown". The car's weight will force the wheel to the center, that is your self-centering effect.

So if you double the caster, say from 2 to 4, you will in effect be doubling the force required to turn the wheel. At speed you may really love it, and it may feel better. The trouble with MS is how much the effort drastically increases in a parking lot, while stopped, or moving at very low speeds. The increased effort is due to tire friction to ground. It is obviously very high when stopped. Drivers of MS cars know this very well and instinctively let the car move forward very slowly before they try to turn the wheel as it requires two strong arms if the car is perfectly still. So because tire contact patch friction is the primary force when slow, you may not feel very much difference by doubling caster. It would increase, but I would not expect it to double. However at speed that effort should double, and you may love the increased feel.

You 77 is manual steer, and IIRC you are running 2.5 castor. It would be relatively easy for you to experiment with it and see if you like, or not, the increased effort at speed, and at parking speed. No need to visit an alignment shop for a test. Just write down exactly how many shims you have now on your four studs, after your professional alignment, so that you can easily return to that. Do not change the TOTAL number of shims on the right side. Just take 1 shim out of the front and put it on the rear stud. You must make equal changes on both sides. When you run out of front shims that is all you can do. Then take it for a spin and see how the "effort" is. Doing it exactly this way will not change camber at all, only caster, and should not change toe-in significantly enough to worry about for a test drive or two. If you notice it gets "darty" all of a sudden off-center that means you dipped into toe-out. Just ignore that and concentrate on the effort required to turn the wheel.

I figured you would like the experimenting. And then you could find the "caster vs effort" balance that suits you and your driving style.

If you find you want to try more caster than what the above method will give you, that is when you need the offset shaft, or the slots, or both.

Example with numbers:
My factory 70 Z28 race car had a 10-15 in/lb steering wheel effort measured at the rim Factory PS gearbox and setting. One finger steering effort. Almost no tire feel at all. Horrible actually. An 86 IROC had the best highest effort fastest ratio recirculating gearbox ever to come out of GM and it was used in race cars for many years. Much better feel. Effort was 30-35 in-lb. I had my gearbox rebuilt by Tom Lee of CA to Nascar specs to 50-in-lb effort. I LOVED it after that. I also ran 6 degrees pos caster. Everyone that drove my car thought I had very good manual steering with terrific road feel, or a rack-n-pinion setup, but no one could believe it was PS. So maybe that is a good manual steering in-lb reading to shoot for. However my PS wheel effort was exactly the same at high speed or low speed. If I had to hazard a guess it would be that the PS assist did not even kick in until the car was at low speeds where the 11" wide slicks required considerable effort to turn. I drove a similar friends car with MS and could hardly get it to turn in the pit area at all, my arm muscles weren't big enough! LOL And mine still felt better on the track than his at higher speeds, so suspect I was running much more caster.

 

Took my front and rear bumpers to Pauls Chrome north of Pittsburgh today........very pricey, but they are original parts, and will be better than new once they finish the re-chrome job.

 

I used to live out that way many years ago. Seem to remember they were in Mars, PA, but heard that the business had burned down. Good to see that they are still operating as they did have a good reputation!

I use Librandi’s here in Harrisburg. Like Paul’s, not inexpensive, but you get what you pay for.

Regards,

Stan

 

It's good that you have the fat piggy bank to make them look new(er)!

 

Been making slow progress on the project, mostly getting things that others will need to do, scheduled. Also been blasting parts in the modified Harbor Freight blaster I spend last summer building?!. TODAY I received what I consider to be the "key" focal point of a black 69 Corvette,......and that is the TJ2 optional louver inserts that fit into the front fender gills. These are absolutely MANDATORY on a 69 IMO, and on a black car is one of THE focal points of beauty on a very beautiful car. I know they make these aftermarket,.....but I wanted NOS versions, due to the importance of quality and fit of this very important part.

Thanks to forum member Ken (C3Stroker) for selling me 5 of the 8......and I just found the remaining 3 I need on Ebay, making a full set. They ended up a little more $ than the reproductions, but for these parts, I felt it was worth it.

 

Received tach, speedo and cluster gage packages back from D&M Restorations. They repaired, tested and calibrated all the instruments. Everything looks excellent. Had them install new tach face with proper RPM caution and redline for big block. And retained original mileage on odometer.

Have frame on dolly, preparing to weld up all the un-welded frame "skipped" areas, and install patch plate over front crossmember where the typical dents are. I am also replace one of the two lower A-arm mounts where a previous repair was poorly made. Checked rough alignments on the mounts, and everything so far looks very straight.

Gary Ramadei is preparing to build new trailing arm assemblies, with all my original cast parts, and the new stuff required.

 

Thanks for the detailed updates

 

Gary Ramadei has finished my trailing arm rebuilds, using new Bairs arms, most of my original cast parts, new brake shields, new E-brake parts,........all put together with all the exceptional detail that Gary puts into these rebuilds.

And Jody Haas has finished the Autogear M23Z 4-speed transmission rebuild for the 77. And now he is starting to build the same transmission for this 69.

I will be making a road trip soon to pick up both the trailing arms and the transmissions.

Waiting for Mark Jones at VortecPro to have time to work on my 406 and the big block 468. .

 

I am currently undergoing this exact same process for the same reason. I have double check measurements for you.
Those two a-arm mounts appear to be 16" from center to center, both front and back.
I see you already have a centerline marked, excellent!
One of mine was 3/8" off.
Measurements from 11 or 12 cars:

 

Blue/Blue is the absolute best combination in 69. I have a red 72 Conv and would love to have a blue blue car.

 

It is one of my favorites as well.......something to consider. I really like black, but the painter I used for my 77 REFUSES to paint a Corvette black....says its too hard to get right, always shows defects, and says I am too picky. Probably get a different painter,....or try it myself??

By the way....I love Zip, get most of my stuff from you guys. Your catalogs are the best and you always do the right thing on bad parts, etc. Thank you for that.

Some year I am going to come down to your Annual Corvette Show.

Jeff

 

Thank You

 

black is a mirror. shows every flaw. so my 75 is gonna stay white.

 

Enough said......in one picture. Undeniable.

 

Gorgeous!

 

As long as you don't drive it. If you do then it stays dirty.

 

Yeah.....I have heard that all me life. I ride black Harleys, owned black pickup trucks, wear black clothes,...but it is more important to me what they look like when clean than worry about when they are dirty. I am not compromising just because they get dirty once in awhile. Any dark painted car suffers the same issue.....not limited to black. I like cleaning my machines.......its all part of taking care of them. Doesn't scare me. As I said with the picture I posted......just look at how sweet that looks. Enough said. Undeniable.

And......I will drive it alot....I promise you. I put 8000 miles on my 77 last year, as well as 5000 miles on my BLACK Harley. FYI......that bike has 137,000 miles on it, all by me.....the paint looks as good as the day I bought it in 2004.

 

Yep...youre a fan of Black and Chrome roofless vehicles too !

 

Great thread. Following along. Find another painter and stick to the plan. It’s a good one.

 

I will enjoy your build progress and what's a m23z 4 speed I have a t56 in my 69 that fits with no problems and love it .