The initial CA and federal emissions standards were only for HC and CO. The NOx issues came later. The earlier cat converters only did HC and CO, not NOx (which was the later three-way converter). Same with GM and others.
The CHP cars were CA-spec cars, but through some holes in the CARB statutes, they could remove the muffler and do some other tweaks to improve pursuit performance. 1979 and 1980, as I recall. The liked the R-car platform but not the performance of the CA-spec engines. Seems like there was a hole in the federal statutes that exempted law enforcement vehicles from having to meet the fed emission standards? But everybody usually used existing CA-spec engines anyway.
Chrysler was able to better use engine tuning to achieve their earlier emissions control successes. The CAP system, which drove GM mad as Chrysler did it with a small additional cost as GM and Ford needed to have more expensive air pump systems. It was allegedly the more efficient Chrysler combustion chamber design that allowed this.
The initial foray into EGR was with "floor jets" in the intake manifold. Another low cost item that many grumbled about, but was pretty neat as long as things worked right, if you think about it. Although 1974 was the first Chrysler EGR valve. It was all about a "fine line" between emissions numbers and getting the cars to drive right. GM had their issues too! In general, it did seem that the Chryslers I was around ran better and got better fuel economy than their GM or Ford competitors. But there were also issues of cold-start driveability, for everybody. I could tune that out on my cars, but it deviated from factory spec when I did, but it worked better which should have been "cleaner".
There was a comparison article in the earlier 1970s about how "in-smogging" a motor made it work better and also burned cleaner. Richer mixture, more spark advance, etc. All of which would end up increasing the heat of combustion and NOx as HC and CO were decreased.
In the aftermarket, there is only ONE intake that fits 318s and 360s both. Same with intake manifold gaskets. Much of the things like "small ports for higher velocity" have turned out to be hype rather than fact, from what I've seen. The 360 2bbl intake on my '80 Newport looks like a normal 2bbl intake, except it has a 318-size Carter BBD carb on it. 318-size throttle bores. The carb mounting pad looks "modified" from what it would have been with the Holley 2245 2bbl for a 360 in prior years.
I can't count the number of tune-ups we did, with later displeased customers, as they sought to get "a skip" out of the engine in the 45mph range. That was the speed at which the torque converter locked-p on those 5.0L Caprices in the earlier 1980s. Or the number of phone calls I answered about changing rear axle ratios on a middle 1980s Chevy pickup with the OD automatics.
As it turned out, the dealers put "car/highway gears" in the pickups they ordered. As the GM torque converters were modulated by manifold vacuum, when going up a hill, they'd unlock, then lock-up when the load was decreased. With a 3.08 rear axle ratio and OD, it happened on normal interstate highway driving in hilly terrain. Just as it was supposed to do. If you ordered the optional 3.42 rear axle, that behavior was lessened. Gear and labor was about $1K back then. My suggestion was to wait and get another truck later on as their fuel savings would not justify that expense. When I told them what was happening and why, they understood. Obviously no one else had done that or knew why it was happening.
But, all that did pass with time and more refined computers and engines.
CBODY67
