well like I said I had T-pipes on my boats, so I have adjusted Header lengths before, the real reason I asked was because I knew mine was smaller pipe than a true 60 size pipe, <that's why I asked "if I was asking for too much" from this pipe,
back when I had boats starting in the lat 80s the big thing was to put over size pipes on smaller engines, like a 60 size pipe on a 45, and a 90 pipe on a 60/67
Jim