Hooker to Magnum head problem! HELP PLEASE!

I have Spitfires that have been on my duster with 3 different sets of heads...#675's (70 318), #302's(89 318), and some mid 90's magnum heads. The bolt holes lined up perfectly on all of them. The exhaust pattern is the same. There must be something wierd with those hooker headers...you sure they aren't for W2 heads?