I have a very low mileage '85 Caddy Seville. It is time for a new muffler and I am wondering about removing the catalytic converter. Will this make any difference? The car is severely underpowered and even 5 hp would be noticeable. Is there any other antique smog equipment I can remove? My state does not check cars this age. this is the 4.1, not the 8-6-4.
I'd say yes especially if it's original CAT because it may be clogged. You could hollow it out and put it back on. Take a steel rod like piece of rebar and hollow it out or a piece of replacement pipe and you'll get a bit better flow but probably only notice the sound difference and not the extra hp.
