A.I.R. adjustment brace

[Andrew S.]

Is the AIR adjustment brace significantly different on a 68-69 427 car versus a small block car?
The reason I ask is because I have the correct numbers matching pump and the correct base bracket. However when I try to install the adjusting bracket to the pump, the bottom edge of the upper end of the adjusting bracket is hitting the pump housing and I cannot align the bolt properly. So I was wondering if maybe the previous owner put the wrong bracket on the car when he re-installed the AIR system.
Also does the mounting bracket require any shims because the pulley alignment between the AC pulley/AIRPump Pulley/Water pump pulley appears slightly misagligned.

My car specs are
1968
427
TriPwr
AC
PS
A.I.R.
Any comments are appreciated

[Joe L.]

Re: A.I.R. adjustment brace

Andy-----

The braces are different enough that they are non-interchangeable. Pictured below are both braces. The one on the top is a GM #3921903. This brace was used for all 1968-74 big block Corvette applications.

The brace on the bottom is a GM #3933093 which was used for all 1968-79 small block Corvette applications.

[Joe L.]

Another Photo

Here is a side view of the braces. As before, the 3921903 big block brace is at the top and the 3933093 small block brace at the bottom.

[Kevin M.]

Re: Another Photo

Joe,

I assume those are original GM pieces. It's interesting because it looks like two different finishes but both show signs of a run.

Kevin

[Andrew S.]

Re: Another Photo

Well my suspicions are confirmed. I have the small block brace. Guess I am off to swap meets and Ebay as Paragon shows the part discontinued. Thanks Joe

[Joe L.]

Re: Another Photo

Kevin------

Yes, these are both original GM pieces. Braces like these were almost always dip painted, almost guaranteeing runs.

[John H.]

Re: Another Photo

Kevin -

Plain steel parts of that nature were shipped from the vendors raw (unpainted) to the Regional Parts Depots, just as they were shipped to the assembly plants. Each Regional Depot had their own in-house black prime paint system, and did their own prime painting (including such things as hoods and fenders). There will be variations in the finish, depending on which Depot painted the parts, which were then distributed from the Regional Depot to the GMPD warehouse locations which shipped to the dealers.