OK, Got it open. PHWEW!
Had a friend come over and he pulled on the latch while I used a 1x2 board thru the grille to push the latch pin rearward. Turns out it was a self inflicted wound, as I had the safety catch hanging up a little, so I shortened up the firewall to inner fender rods one turn of the nut. DON'T DO THAT!
It made the latch pin catch on the sheet metal below the latch plate itself, which needed a bit of dremel work to relieve it. It stuck again, and we were able to use the same method to get it open again. THEN I adjusted the rods back to spec and all was well.
Thanks all for the support.
The truck is running, but with a few items yet to check, including valve lash setting, final timing, and checking the battery charge (doesn't seem to be charging - shows slight discharge on the ammeter. Probably either generator, which I rebuilt or the voltage regulator.
