Look up headers on the net if you haven't already done so. I found DynoMax, I am pretty sure that is who bought out the company that made mine.
What trouble have you run into that leads you to believe that the headers you looked into won't work with angle plug heads. I know a couple of folks that used the same headers after changing from straight plug to angle plug heads on F-bodys. I'm sure that in some cases they wont' work. I probably have the same header you would need on my car since it's an F-body but a 73 instead of 79. My headers worked with both heads, as I said they actually work a whole lot better with angle plug heads than with straight plug heads.