Take a white marker and mark the headers where the plugs are. Take the headers off and hold a piece of wood over the white marks and hit it with a hammer to bend them out of the way.
Are these headers made for the 40P heads or the 302 heads? If you can return them and get the correct set would be the best thing if not slam away.
1968 Coupe <53000 miles on her 289 came off the line Jan 21st 1968. I bought it in 1983
2013 Shelby GT500 Born 12/06/2012 number 439 of 530 in DIB and 1 of 9 with Red Stripes over the top and on the seats