Reading this post we have different conversations going all over the place, from 428 to Olds power boats.
Let's start with emissions. Thank you, California. Yep, that's where it began. 1961 an administrative organization called the Motor Vehicle Pollution Control Board (MVPCB) was created. Later changed to the State of California Air Resources Board in 1967.
In 1961 the board required all new motor vehicles sold in California to have crankcase emission control devices (namely to control engine blow-by gases) as factory installed equipment aimed at reducing hydrocarbons down from 1.25 pounds per car per day to 1.0 pounds. This changed in 1966 when unburned hydrocarbons had to be limited to 275 part per million (ppm) and the carbon monoxide to a 1.5% concentration by volume dropping the pollution levels to .046 pounds per day per car. The projected number that California was looking to see by 1970 was 0.20 pounds per vehicle per day.
Thus began the introduction of the PCV valve, the closed crankcase system, A.I.R. systems, open chamber heads, thermostats changed from 180 to 200 degrees, reduction of idle port holes/limited idle screw adjustments, retarded timing controls and the double acting vacuum advance can, the catalytic "after burner" (yes, 1968), and the gasoline vapor recovery systems. All thanks to California and mandatory on all cars/engine sold in California and this was all by 1968, and of course more was to come after 1968. In other states, some of these requirements were not required and thus a CA car will have the AIR system while one in New York would not, but still had the AIR heads. The better burning open chamber heads did away with the AIR system......but it did return at a later date along with those charcoal canisters if anyone recalls those.
The use of the Oldsmobile 403CI came about because it was the only comparable engine to the Pontiac 400CI that met California emissions standards. So California cars were fitted with the Olds engine in lieu of a Pontiac 400. The 403 was also an optional engine on the Catalina.
The Olds may have had smaller valves (2.07/1.62) and even flowed less than a Pontiac head, but the use of a longer duration and higher lift did wonders for the W30 option. The 1970 W30 455 was rated at 370HP @ 5200 RPM and 500TQ @ 3600. The cam had a 328 duration on Int/Ex, Lift was .475, and had an overlap of 108 degrees! So do you want to compare it to the 370HP RA IV or the 360HP 455? Oldsmobile had some hot set-ups to include the W31 350 with its 308 duration cam and .474" lift and 82 degree overlap cam. Same HP as the Pontiac 350HO, but my guess is it'll outrun the 350HO.
You can also look to an earlier time when the engine option in 1966 on the 442 could be had with the 400CI, tri power, ram air induction, close ratio 4-speed, and 4.33 gears and would have been the match to Pontiac's 389 XS tri power, ram air option.
I have never owned an Olds 442, but I would say they had a few engine options that may have put a hurting on a Pontiac GTO, or a Tempest/Lemans with the 350HO.
