I just bought some Flowtech headers to put on my 86 Buick Regal until I put a 350 or 455 Buick engine in it. I noticed after checking the alignment of the gaskets that it will leak badly. I have the Zone getting me both exaust gaskets for the round and square to see how they fit. It looks like I will have to lower the bolt holes in the heades to raise them on the heads so they will seal correctly. It has the 307 Olds in it. Has anyone here been through this?