By request!
The front windshield channel on my 66 GS was pretty bad. Previous owner had just applied duct tape and Bondo over the holes to 'fix' it! ???
Repo pieces are avail for Chevelles. There is a channel piece, and a dash piece. The defrost ducts are different between The Chevelle and my 66 GS, so the dash repair piece was nearly useless. But the channel piece is the same. About $65.
Note that the part extends below the front fenders.
Removal begins by wire-wheeling the old piece to locate the spot welds. Center-punch the welds, then drill part-way thu to weaken the weld. A spot-weld-cutter also works well.
Then use a thin chisel to separate the pieces:
For the hood side of the channel, I decided to cut a strip off with a cut-off wheel so I could access the drilled spot welds with the chisel:
Separating the partially-drilled welds:
This is the worst of the dash panel. It was cut out, and a repair piece was installed:
First tack-welded, then fully-welded and ground smooth:
I eventually decided to do a full frame-off resto on the car! Entire interior was sand blasted. Here is the area without the windshield channel:
Cowl vent was reinstalled to align the replacement channel:
Note the holes drilled in the replacement channel. This is where the new welds will be. A mig-welder is used to weld thru the holes, joining the two pieces. This technique is called 'button-hole-welding'. It's a great way to reproduce the factory spot welds.
All welded in!
After this, the posts for the molding clips will be spot-welded in using a auto-body stud welder. It will reproduce the factory molding posts EXACTLY. ;D
This isn't an incredibly difficult job. But it does require removal of the front fenders.
If you can just patch the existing channel, that may be a better option....
PLEASE realize there is a fire hazard from the grinding and welding involved...the firewall insulation is very flammable. It may smolder for hours before it bursts into flames!
Have fun, but be safe! ;D