1969 Dodge Dart Pro-Street 440
Ok scrap everything I said. I figured it out. Go to block layer.com there is a calculator that allows you to print templates of everything to build a house. One thing in there is cutting holes In a roof. Tell the calc what the pitch of the roof is and the size of the pipe and it will spit out a oval to print and trace and cut.
My dash was 30.5 degrees and gauges are 2.5 inches.
Print
Trace
Cut
Install!!!!
Headake over!!!!