I am in the process of fitting a new chrome bumper on my 69. What is the true acceptabler tolerances from the factory. I did not find anything in AIM. I think I was wanting a 1/8" + and he is suggesting that 3/16"+ is acceptable and more common. After discussion - I am thinking he is correct. I just find it frustrating that the clearances on left vs. right can be so drastically different.. yet I do realize the cars are never 'square.

 

I don't know what the excepted tolerences are, but I bet your fit problem is the bumper, not your car being un "square".

The repro bumpers are notorious for this, mainly the ones made by Keystone that retail for $299.00-$325.00. These bumpers tend to have one side (the right?) stick out further than the other. Seems to me, if you get the center and one side gapped right the other end sticks out too much. If you pull in the side tips, then it forces the center out, causing an unexceptable gap there. The bumpers from Paragon are made by GM's original supplier and may fit better. I think the retail is around $360.00-$375.00.

 

You are correct - the right side sticks out farther.

In fact after hours of testing and measurements, I find the center bracket on the bumper is 1/4" off center. THAT pi$$es me off. I may go back to my old bumper and have it re-chromed.

I am not sure yet - but that same center bracket may be twisted down, which upon tightening, pulls the bumper far away from the hood surround front edge.

In shipping, the right extension bracket was bent. And the left bolt area appears to be welded on a bit tilted.

Seems like they could get it on the money for the money we pay.

 

As a parts vendor, I learned this the hard way. I sold a couple of the $299.00 bumpers and had customers come back to me complaining about the fit. I no longer sell the $299.00 bumper. If your original fit well, I would concider replating it, but be aware that it could take months to get it back. You may want to live with the repro while the original is rechromed and then sell the repro later.

 

The '68 AIM shows up to 1/2" clearance is acceptable. Smaller is better. I managed to get the bumper on my '68 to about 3/8" all around and fairly straight.

 

My brother says 3/8" min is at least the std front bumper clearance. He noted the front bumper eclearance was a bit larger than any other bumper chrome

 

This is a OE bumper that has never been off and is close and nearly equal at every point. I never measured how far it`s away from the glass on a no hit car. I would say a 1/4 or less. When I go back to the warehouse i`ll take some measurements and list them at different points....




Clearances

The center clearance [nose] is 1/2 inch and the ends or corners are both 3/8 measured at the top of the bumper

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Nice early '68. Is this an L-88 car?

 

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There is a story many know of behind this car and involves Fords 427 Cobras and this particular 427 Vette. Ordered and purchased with the highest horse power available and no power assists it did not measure up to a 427 Cobra as expected. Rather than order another car the dealer agree to warranty the 435 HP engine with only 200 miles from new and install the lower 430 HP engine that is now more commonly referred as the L88. Which was well over 100 HP improvement with the swap. This at the time appeared to be the most satisfactory solution with finally the correct result. I had no idea that the car would still be here after 40+ years and still with only 28087 miles...