I would think the dogleg exhaust port size is generally a bit larger, in addition to the actual dogleg itself. My experience with header gaskets has tought me that you are going to want the most gasket sealing surface possible. I have a crap load of end piece header gaskets around from when I was running a pair of Headman headers. I decided to cut the bracing between the front and rear pipes, seperating them from the siamesed center ports because I thought it would have a
cleaner appearance and give me really good access to the spark plugs. After a short while, I started blowing the center gasket about once a week! The thin, light duty flange was warping because of the lack of stiffning that the full lenghth flange might have provided. I replaced the Headmans with Hooker Super Comps, but even those didn't have the most precision of port matches.
What I am getting at is, I've noticed there isn't much mating surface on the heads nor the headers in some spots. I used some of those end piece gaskets just last week to fix a leaky stock manifold, I had used two square port end pieces and trimmed them out to fit the dogleg, so if the Square Port gaskets are anything like the Square Ports themselves, I think your pushing the limits on getting a good bite on the sealing surface area. How about getting some bulk header gasket material and, using your dog leg gaskets as an Outside template, cut some of your own (make space for the
head bolts that are just under the ports!) That is if you can't get the Square port gaskets themselves.
It's worth it to get the best seal and port alignment the first time. Leaks are a pain in the **** and they can warp the flange pretty quick sometimes.
Sorry about the lenghty and wind-filled answer, but I wouldn't want you to go thru the same hassle I had to! Also, open Header exhaust is like Mozart or Bach, or Beethoven, to us safisticated and dignified individuals and shouldn't be detrimental to your engine. I think exhaust leaks
right at the cylinder head might cause some problems in the long run. but open headers are something eveyone should be
forced to enjoy, especially at 2AM on a cool summer night!
