[War eagle]

Actually I believe I am correct and the center supports are identical and add to the structure strength. You must look at the center supports again John and note they are not mastic attached(whatever that is) but rather resistance welded to the "wall" of the shroud panel as well as the leading edge of the firewall.

The resistance or "spot" welds have been used in auto construction as well as other products needing a great deal of strength beginning in the early 20th century. In 55, Chevy announced that 92 % of the assemblys were joined by spot welds. That number peaked in the 1990`s and currently is going DOWN with the use of super adhesives.

For clarification, the dash rods at steering column dash mount, attach to the left of the left "center" wiper link support and also thru the left outboard support. One could assume that a right hand drive Tempest would use a right outboard support to also attach the rod to the the lower dash.

[John V.]

Yes, the supports are spot welded in place. I made mention of that in my post.

I described the strip of sheetmetal that fits between the windshield and the louvered vent panel as being attached to the supports by mastic (which is a generic term for sealers/adhesives). Mastic was specified for attaching the hood skin to the underlying structure as I mentioned.

This piece of sheetmetal gets painted body color, it is external sheetmetal. I do not think it was separately serviced unless you can determine otherwise.

Without deconstructing the upper dash & duct assembly, I do not know what that strip looks like as an individual part before it was made part of the upper dash and duct assembly.

All I can see is that there is mastic between it and the center supports where it crosses them. I suspect there may be mastic all along this body piece and a formed lip beneath it. The mastic appears to be all that holds this strip in place. Note, it is not attached to the driver side support, I can't make out how it is fastened at the ends.

I disagree with your notion that spot welds provide a great deal of structural strength. But that is a quibble based on mechanical properties of various welding methods and other joining systems which provide greater structural load carrying capability.

They have been very well suited to automobile body construction as you point out. Largely because of other attributes, among them economy.

I am not sure what you mean by dash support "rods"? Only thing I see attached to the supports is the wiper linkage. Adjacent to the unused center support is something from the interior which bolts thru to a thick square backing plate on my car, haven't tried to determine what that is, but the connection is independent of the supports.

I guess I'm just cringing at the idea of structural strength being attributed to these supports.

I don't think I am disagreeing with you at all, just think the idea of structural strength is misleading, I don't get the sense that the support is intended for load bearing, not to any significant degree at least.

The supports used for the wiper linkage definitely provide a rigid mounting for the loads induced by the wipers.

The extra center support may have been to add some "rigidity" to the dash assembly, perhaps to control "flutter" in that area.

Maybe once I understand what you mean by the "rods" you mention, perhaps these rods are inducing a load. Just not seeing that at the moment.

I think we both agree, the "extra" support is not extra at all, Fisher put it there for a specific reason and I'm now pretty convinced it was unrelated to Right Hand Drive, something I was skeptical of even as I suggested it because that is a pretty "expensive" piece of metal to add to the build if it had no purpose except for a rare Right Hand Drive equipped build.

It is likely a structural reason, so I guess I should just accept "structural strength" as the descriptor.

[War eagle]

I found in Grp.12.803 Cowl and Dash Asm. (L.H.D) but nothing leads to the Right Hand Drive in the 64 MPC.
The "rods" I made reference to are found in group 6.750 support assy stg column.

[John V.]

Ok, got it. The LH rod threaded into a nut and attached at the driver side support. Didn't notice the penetration in that support yesterday.

The RH rod is the piece I did see yesterday and noted, doesn't hit a support (least not on mine), connects to a thick square plate adjacent to the unused support. I think (didn't look close) the square plate is spot welded to the Dash Assembly, same as the supports are. But since it is independent of the support, doesn't seem the unused support has anything to do with it.