C3 Front & Rear Height
Thread Starter
Intermediate
Joined: Jul 2019
Posts: 28
Likes: 3
From: Massachusetts
C3 Front & Rear Height
Hi everyone started the restoration on my 1978 Silver Anniversary Corvette, first thing i noticed is the rear of the car sits about 2 - 3 inches lower than the front. I did put new tires all around the same size.
When driving it is considerably noticeable from inside.
Is this normal for a C3 or am i looking at a suspension issue.
Last edited by Ricksr78; Sep 2, 2019 at 07:24 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
From that photo, it looks as if the front is too high. If you ride over some significant bumps and the rear does not bottom-out, the rear should be fine. The Chevy Chassis Service manual for 1978 will specify the proper ride height as a measured distance from ground level to the underside of the frame, both behind the front wheels and in front of the rear wheels.
For 1971 (the only chassis manual I have) it specifies approximately 8" for that distance. The 1978 car had somewhat larger tires than the '71, so that frame-to-ground measurement might be a bit larger. But for the car to ride level, those measurements inside of the wheel openings should be nearly the same.
Making those measurements should at least let you know which 'end' has the problems.
For 1971 (the only chassis manual I have) it specifies approximately 8" for that distance. The 1978 car had somewhat larger tires than the '71, so that frame-to-ground measurement might be a bit larger. But for the car to ride level, those measurements inside of the wheel openings should be nearly the same.
Making those measurements should at least let you know which 'end' has the problems.
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
Top of will well arch to the road should be around 27 and a 1/2 inches front and back. The rear drive axles should be roughly parallel with the road. Not tilted down Hill not tilted uphill.
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Melting Slicks
Joined: Sep 2004
Posts: 3,227
Likes: 670
From: Northeast
Asked my friend who is the original owner of his 78 (225/70/15 tires). Just has a few thousand miles on it. He measured from ground to lip in the front 28 3/4". Ground to lip on the rear 28 3/8". Entire suspension system is original. I measured my 78,( 255/60/15) and it sits at 28" front and back. I installed 8 inch spring bolts to lower the rear .. .
Racer
Joined: Jan 2007
Posts: 308
Likes: 18
From: Sweden
Throw in a big block, that will make the nose come down a little... 
Look under the car at the rear suspension. 1/2-shafts should be parallell to ground or tilded down sligtly. The spring should have a little arch (i.e tips closer to ground than the milddle).
Also check the spring bolts. If there are threads left and you can tight the bolt, the rear will come up.
Someone could have added longer bolts to lower the car. Shorter bolts will raise the rear.
/Johan
Look under the car at the rear suspension. 1/2-shafts should be parallell to ground or tilded down sligtly. The spring should have a little arch (i.e tips closer to ground than the milddle).
Also check the spring bolts. If there are threads left and you can tight the bolt, the rear will come up.
Someone could have added longer bolts to lower the car. Shorter bolts will raise the rear.
/Johan
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,601
Likes: 7,046
From: New Or-leens Loo-z-anna
My '68 springpack......all the leafs are fairly flat...you can easily see the end of the main leaf is starting to bend upwards from age....that bend and flat leaves will cause you to lose an inch or more in body height at the rear wheel well. (I installed the bolts upside down for looks)
Last edited by doorgunner; Sep 5, 2019 at 10:44 AM.
Instructor
Joined: Jun 2015
Posts: 182
Likes: 21
From: Alger Mich
Rick I have the same car,L-82 auto,with Gymkhana susp with 255/60r15" GY tires with 15k on them,36k total on car.. My frt fndr lip to grd is 28 3/4",rr is 28 1/4". Little over two fingers btw rr tire & fndr lip. Nothing hits or rubs even hard over turns. Hdal
