I may be able to get a good deal on a set of GT-40P heads and I was told that some longtubes headers will work. Well I dont know exactly what brand of longtubes I have on my car because they were installed when I got them and the previous owner doesnt know either. They have a 1 peice flange and on the stock heads a couple of the spark plugs are very hard to get off because of the headers. What are the chances that my unknown longtubes will be a direct fit with the P heads (with no or little spark plug clearance problems)?