Should I do a Cat delete on '75 Duster

remove cat and replace the 1 7/8 pinched head pipe with a 2.25 super six size. While your at it, recurve the distributor..reset base timing to 70 specs, shave .090 off the head...wait, your getting a hemi? Chop the cat off and get an old carb and remove the timing delay thingy. When I was growing up in CA, the Smog cut off was 1966 so I got a 65. C.A.R.B. (smog nazis) in CA are assholes. Try and get a pre 83 car to pass smog nowadays with all the smog crap vacuum pots leaking and anti backfire valves not working anymore and are no longer available. You can plead your case to a referee (parts no longer available) but those guys are on the spot for passing cars too. One gets past them and they lose their status. My Mazda would only test in second gear and I had to go to a referee for that.."RPM to high at 30 mph" was the stupid machines excuse to fail, and they (test only station) could not test in second gear per their rules. "ever hear of gearing?" That is how STUPID CA smog laws are. OK, back to your Duster......