are there different sized steering couplers?

just wondering about this....

i have a slant 6 power steering box and column in my car and now have a 340 that i bought some heddman headers for...they are supposed to work with smallblocks with power steering and 4 speed linkage (both of which i have) and theses same headers have worked fine for other members ive talked to , with no dented tubes...however, one of my tubes hits the steering coupler pretty bad to a point where im going to have to dent the tube....as much as this pisses me off, im just wondering if couplers were different sizes, or if i just have a bad header, or bad luck...theres no way these headers are going to clear without beating em in