Best "no problem installing/clearance header
Well, I just installed Hedman (
http://www.summitracing.com/parts/hed-78050/overview/year/1970/make/plymouth/model/duster) into my 1970 LA, 4 Speed, manual steering car.
Just to let you know, this was not a fun task, I removed the drag link, steering column was out and starter needed to be put in from bottom (Large one). Driver side needed two ding areas - one on #3, was hitting the head casting and either #5 or 7 (cant remember) was too close to the starter.
Also - #5 and 7 are going to be a PITA for plug wires.
This is my experience