I went on vacation after Christmas and didn’t get back until mid month. Just getting back to work on the Plymouth. All my parts were waiting on me when I returned. After working today, I’m much more confident that the big block Chevy headers are going to work now.
The Plymouth frame rails narrow from the rear to the front like many other 30’s cars. This causes some difficulty trying to lay out the header side pipe arrangement. I don’t want the collectors and side pipes to extend out horizontally to far from the frame. I also want the side pipes centerline to be at near the same height as the bottom of the frame rail. I also have to make sure the header front tube doesn’t interfere with the front tires and fenders when I turn stop to stop.
This was hard to figure out by just eye balling it so I made an adjustable holding fixture to clamp the collector in place at the right height and distance from the frame. It adjusts horizontally and vertically. Once I found the right spot I locked the collector in position and I’m building the headers from there. This worked really well allowing me to cut the header primary tubes back in a controlled manner in order make up and fit the transition pieces between the primary tubes and the block flanges.