when did catalytic converters start?

[Princess Valiant]

74-75 was sort of a transition period based on where the car was sold, and the exact engine combo. Pretty much all cars in 76 and most light trucks in 79.

Running a cat shouldn't be a big deal if your A/F ratio is reasonable and you burn more gas than oil. Yeah, it's one more part, but they do a LOT to clean up unburned hydrocarbons. New cats aren't particularly restrictive either. The worst cat now is light years better than the best cat then.

well the original cat is long gone but it was a slant six/ auto.

I was mainly baffled as to why there is a bump in the floor for the cat when this is definitely a 74 model year car VL29C4G208XXX

 

[the67fish]

Had a 74 Chevy with one, dont know about sooner than that.