I am going to buy 2 new HF jacks that are on sale this weekend and don't know if I need the low profile model so I need to know what the clearance is between the floor and the bottom of the car using standard jacks pucks.

 

Dont have your measurement, but have a "Daytona " from HF. Went low pro and it fits. The low pro's go up pretty high, bet it would even lift my 2500HD if needed. Btw, I went 3 ton because of the frame stiffness, some points you lift more of the car than you even wanted.

 

Sorry, don't have an exact measurement answer BUT my long reach, low profile jack with a 2 inch high jack pad has ~1/2 inch clearance with the ~1/2 inch extended saddle lip I added. Looking at the jack specs, min lift at to of saddle top with the standard saddle height of ~1/4 inch and using a 2 inch high jack pad (which I have done) I have there is ~ 1/2 inch clearance to get the jack under.

So with the advertised min height on 2 3/4 inches, adding 1/2 inch for the extra saddle height I added that is 3 1/4 inches to the top of the saddle.. With a 1/2 inch clearence to my 2 inch jack pad (not the 1 inch shown below) that is 3 1/4" at top of modified saddle. + 2" high jack pad + 1/2 inch clearence = ~5 3/4 inches. Suggest buying jacks with a 15 or 16 inch long jack arm NOT the short 10 inch. Because it is light and easy to position I use it IF just removing a wheel with ~1" gap from tire bottom to ground.

Note, have 4 Harbor Freight Jacks. The recent heavy, 95 lb, long reach jack I bought was NOT moving into the car (as needed to keep the jack saddle directly under the jack pad.) So I welded an extension to the almost none existent saddle height. With t jack pad in place it pulls the jack into the car as you lift.

 

Looks like the low profile jack is in my future.

 

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FWIW, many are "low profile." The issue with usually the least expensive small (10 inch arm in my case) jacks in addition to limited lift capacity (mine is 14 inch max from the lowest position) is they have to move in further at it's max lift. That is hard to understand if you have not used them. As see in my pics. my small arm ~30 lb Race Jack jack MUST move into the car 2.6 inches at it's max lift. If it isn't put perpendicular to the car, the rear casters are not positioned to move in it will NOT move in the 2.6 inches required. So if started centered on the GM 2 1/2 inch diameter lift pad the car will slip off! NOT GOOD. Frankly I would not buy the 95 lb jack again IF a shorter arm, lower weight jack would be sufficient.

Problem is they do not list the Jack Arm length in specs. If you can - go to Harbor Freight and measure the arm length. Might wait for a sale or check if their 20% off coupon works for the jack. Can only buy one item with a coupon so bring a friend!

 

So C8 still have rear caster?! Man it was and still is such a headache finding alignment shops that do rear caster for C7. They are pretty far away or a lot more expensive at this one dealer.

(My C7 shortly after alignment I hit something in the right front tire and after that it started pulling right, only right front tire went though that large construction metal plate thing so rears are fine. For that case is it ok to just have front adjusted only since nearby shop doesn't do rear caster?

C7 you needed to take the car in for an alignment as early as you can after purchasing it new, since the factory alignment is horrible and tires will be ruined if you don't get an alignment as soon as possible. So is it the same for C8?!?!?

 

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Yep the rear IRS the has a caster setting as part of the suspension and handling design. However they are separate adjustments from camber. Frankly I would not left any Tech who did not have a lot of experience mess with caster adjustment. It's requires special tools to measure and most alignment machines don't! There are forum reports where folks had major tire wear and some handling issues after rear caster adjustment. Like the front caster most are within spec.

I would not take the car in too early for an alignment. Need to have the suspension rubber bushings, sway bar ends etc wear in. Best at 400 to 500 miles. In my case since we have few pot holes I made sure I have driven over some RR Crossings with a rough surface! Also although you can drive a truck thorough the GM allowed camber spec caster is not that far off. Best the average tech doesn't mess with it.

My C7 Grand Sport rear camber was near the max -1.7 in GM allowed range of -0.5 to -1.7. I had them adjust to -0.8 (I don't track.) However my C8 camber were all at about centerline when I had it checked free at 450 miles. One rear toe was out of spec needing adjustment. The ridged C8 frame with 6 large castings and less welding is probably a factor.

Compared to the C7 with an all welded chassis the C8 uses 6 large castings. Each also has integral cast gussets that add to rigidity. Where a welded chassis will yield some high stressed weld areas created with shrinkage as welds cool, those castings make a ridged chassis. As Tadge said in an interview re the C8 chassis being very ridged is essential so it doesn't act like an undammed spring when one wheel hits a bump etc. Particularly an issue with transient movements on high "g" turns.


SIDEBAR
To understand why some "factory" alignment settings may be off after the car is driven some miles, this experience many years ago may be of interest. When most cars used a steel frame chassis years ago, I was touring with the welding engineer at an AO Smith frame plant. They were making Cadillac frames. At the end of the line they had a very simple checking device and a way to get a frame out of spec to pass. There were simple limit switches on a motorized screw that touched the frame in all 4 corners. If it was out of spec, 4 large hydraulic clamps grabbed the corners and twisted the frame to correct any misalignment.

I recall the welding engineer laughing saying when Cadillac checks that will all meet their spec but the first time the car goes over RR Tracks it will be out!

We were a sponsor for Richard Petty for >15 years. They always wondered why some frames handled better than others. I pointed out that the weld sequence of the many tubular frame members was such than some areas were highly stressed as the welds cooled. The first time the car went out on the track some welds would yield and change frame shape slightly! Recall a video where Don Schumacher, the Top Fuel and Funny Car owner showed a dragster frame being fabricated in his shop. They had two TIG welders making simultaneous welds of the many chassis members. One on one side and other making the exact same weld on the other!

 

Thanks a lot so C8 still got rear caster, I am looking for excuses to sell the C7 Z06 and get a C8 Z51 heh, also rear caster is such a hassle! But I am looking at everything and I will probably still sell the C7 Z06 since the used car market is so crazy now.

So 500 miles or so before getting the alignment, got it! No railroad here but plenty of speed bumps, car should settle in in no time. And 500 miles perfect to get the oil change and alignment at the same time!

(Off the topic question C8 cabin doesn't get hot after driving it for 45 min since it's MR now right? C7 after 45min or so the cabin will get hot from the torque tube, I really hate that!)

 

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Yep no aluminum housing torque tube holding exhaust pipes getting hot enough to melt chocolate in the console! Not only won't get hot they put so much insulation between you and engine it's much quitter than my two C7! They even used glass twice as thick as a windshield between cabin and engine. Downside is you don't hear NPP as loud unless window is open!

 

Wow that's awesome, the NPP sound difference between the cabin and outside is already pretty big in C7! I love how quiet it is in C7 cabin they did a good job, can't believe it's even better in C8!! I am even closer on getting the C8 now! Going to see couple C8s in person, see how bad the blind spots are and I am pretty close to put down a deposit.

 

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The C8 has the least blind spots of any car I every owned! Have to get the 2LT or 3LT or Vert to get the very impressive "TV Center Mirror!" Best thing since sliced bread.

I'm one for knowing where everybody is around me at all times. Been doing what the 1990's SAE tech paper said re defensive driving before it was written! They said it's not just the folks on your rear fenders BUT those who will soon be there that are key. Need a good view of the rear. My two C7 coupes did not have good rear visibility. In fact my 2017 Grand Spot with Stage 2 Aero option had extensions on the sides of the rear spoiler. Made rear view like a rag top Vert with the top up. Never needed or used a "blind spot mirror" on my 1988, 1993 or 2008 Vette Coupes. BUT added to my 2014 and 2017. And yep have my mirrors set "correctly!" Doesn't help if you read the right side of the graphic below.

You'll love that center TV mirror. Can see three lanes wide the way I have mine set. You also get "blind spot detection" that shows in the mirrors only with 2LT and 3LT.