Headers for a big block a body?

I have a set of tti big tube headers on my 383 that I got from another cuda owner. I think they must be the RB headers because I had to beat the crap out of one of the tubes that go around the mini starter just to get a 1/8" clearance. No way an original starter would fit. I also had to 'clearance' them at the pitman arm / center link area. If the motor was taller, ie an RB, I think mine would fit nice. Passenger side fit like a glove. Now I have a set of coated / expensive headers that one of the driver side tubes is closed half way ! I will eventually cut the tube and move it over to make it right.