Don't think the port size of the gasket will matter that much. I just used metal intake gaskets on the stock 318 I just built, it's all that I had room for, a 1213 would have been too thick. To help setting the intake down, I cut 2 3/8th" bolts down to about an 1" or less, cut a screwdriver slot on one end. Then screw them into the end holes on one head a turn or two. They will be a guide or target when setting your intake on. Get a few bolts started and then unscrew the two studs. The intake port sizes are pretty much the same except for some of the race stuff.
