Update: long time coming......
I have not posted a reply in a while. I have been looking for a donor cab with a good firewall and cowl. I did not think it was going to be that hard. Well, I tell you, I have looked at over 10 cabs/trucks and all seemed to have the same issue. The seam above the ebrake where the center section of the cowl joins the right and left sides were all full of cancer.
I finally found a 71 GMC LWB that had exactly what I needed. At first I thought I would just use that cab to replace mine but the more i looked at the patch work quilt the cab was I decided that the best part was just the cowl, firewall, and roof. I decided to buy the truck anyway and part out what I don't need which is basically everything but pieces just mentioned. Anyway, here are some pics. If you see something you need let me know, odds are I don't need it.
This is what I started with.
This is what I needed from the truck. Man that was a lot of work.....