I tried this on a different thread, but it was kinda long, so we'll try again. Anyone know the correct procedure for determining the number of shims on the body mounts? I can't find any measurements for this. I did my dry fit on the front end, and it seems that the nose is tilted slightly forward. The frame extension and rad support are both maxed out in the upward travel, and the rocker does not line up. I'm thinking of shimming the rear of the body slightly higher, but have no data to go on. Any thoughts? :confused:

 

I don't think there are any exact number of shims that should fit at each mount. Due to the variations in frame and body, the number of shims was probably determined from measurements. If you get a copy of the Assembly Instruction Manual for your car, there is probably some documentation on height measurements for different points on the body.

 

I have the assembly manual, and can't find any of these measurements. It seems any measurements from the ground would be altered by tire height, tire pressure, new springs, etc. I was hoping there would be some sort of reference from the frame. If not I guess you just wing it and make sure the body is square to known reference points.

 

That's probably your best bet, unless you can find a definite point of reference. I know that one of the Corvette books I have mentions keeping track of your shims and locations so that you'll know how many go back when you reset the body.

 

You wont find that in there. Here is a link the NCRS site, I found this in the archives, I hope it helps you.

http://www.ncrs.org/forum/archive6.cgi?review=14856

 

Thanks to all of you guys. Great info and really fast. When I got my car the body was already off the frame, and the guy had thrown away the mounts. The car was in an accident, and he had already had the frame straightened. (Not a bad hit) I verified this with the shop that did the frame, and they showed me the work order with frame measurements, etc. I then had a friend of mine in the frame/body business verify this with his own gauges. When I got around to setting the body on the frame, it sat perfect at all eight mounts with no shims, so I didn't use any. Now it seems that the back should be higher because of the nose not fitting properly. Does anyone see any harm in maybe 2/3 shims at the rear and working forward for fit?

 

I don't see any harm in adding a few shims to make her fit.

Were the shims used in the later C3 years with rubber body mounts ?

I thought they were used in the solid mounts of the early C3s, but not the
cushioned ones. I had decided to go with cushioned mounts on the 72.5 -
just to avoid the use of shims. Also, I bolted the birdcage down without shims
when replacing the WS frame to try and match the body to frame. The doors
are on and seem OK. I hope I don't have door alignment issues in the future.

:seeya

 

I also don't see anything wrong adding some shims. However I would check for grounds clearances as per assembly manual and check distance from top or tires to fender wheel well. I would think they should be close comparing front to rear. Make sure that rear mounting cages are in good shape and have not rusted or broken thru. I read some threads where this has happened. I would be a little concerned that you have taken up all your adjustments in front and it still requires some upward lift for proper fit. On mine I currently have only one shim (factory installed) on drivers side front. My frame extension still has about 0.5 to 1.0 in upward travel. I have about 0.5in clearance on frame extension supports that are inserted through the inner fenders (the inner fenders are not resting on the frame extension support). The actual bonding areas on front inner feners to outer fenders is about 0.75 in. In other words The bonding surfaces of the inner and outer fender did not flush up to top of the outer fender. About 0.25 in. from the top. This was also the positioning of the original fenders when I removed them. There is a support rod that goes from the radiator support to the metal support of the hood surround make sure that is installed. Let us know how things are going, hope this helps.

 

Do you think that the poly body mounts are higher than stock? It doesn't seem so. The assembly manual for a 79 does list shims, it just says "as required". I really would rather not alter the holes in the frame extension, because now you're making permanent changes.