Thanks for the compliments guys,
I had a hole in the one fender that did not belong...It had some pink stuff filling it. It looked like the same stuff you find in all of the cab corners, rockers and other lower areas of Michigan vehicles. So,I ground it all out and got an education here. Someone had put on a new GM fender back in the day. It still had the sticker on the inside. This is where it gets interesting, if you take the portivent and lay it over the factory elongated holes of a skylark fender moulding,they line up perfectly with no modification. The only difference was the extra hole that they bondooooeeeed in. Having said that,you would not need a template to cut the three holes in because you can simply trace around the vent after you line up the three studs. You would have to start with a skylark fender that had factory side trim if you wanted this to work. The only real issue is just welding up the extra hole. Dan