I still have the original catalytic converter on my 1980 242 with 280,000 miles. No rattles, and passes emissions inspections with flying colors (OK, I probably just jinxed everything). Anyway, recently replaced the head pipe and thought about replacing the cat as a precaution. Price of the exact replacement part from dealer (part #1276727)was about $900 !!!! Obviously, this is a great part as mine has lasted 25 years. However, the dealer also had an "alternate" part number, supposedly genuine Volvo that was about $200. On the parts sheet the more expensive one was listed as a "3-way catalytic converter" while the cheaper one was simply listed as a catalytic converter.

Any ideas as to the differences between these two parts and the expected life of the cheaper one ? Any experiences with fitment and longevity of other brands ? Thanks.

Mike