As for emissions hardware, EGR isn't supposed to happen at WOT. Retarded ignition timing was usually on the lower rpm ranges, not WOT. Leaner fuel curves were part-throttle and not WOT. One of the earlier articles I read on emissions tuning was that the systems were designed to work with the IM240 driving cycle, but that normal calibrations were usually in effect over 3000rpm, which would also be when "cylinder pressure" was in a higher range than it was at lower rpm levels and mixture/timing would be more normalized, generally.
In those orientations, where the main impact of emissions controls were in the lower-rpm and part-throttle operational modes. With EGR, throttle response was not as crisp, by observation. Less total ignition timing could result in less response than in prior times, but still valid response.
I'd say the real "power detractors" included the lower compression ratio (which had some engineering implications, but also resulted in a significantly hotter exhaust flow. When comparing our '72 Newport 400 2bbl and '66 Newport 383 2bbl, the exhaust was much cooler on the '66. If camshaft timing was altered, it was usually "to the positive" with a little more lift and duration, to get more air into the cylinders and then out of them, with a little more overlap in the mix. I never did hear of any Chrysler monkeying around with "retarded cam timing in the cam sprockets" as I did with Chevy and Ford, though. But such a move would tend to help top end power, I suspect, while bleeding off a little low end torque.
IF the flow through the catalytic converter was sized properly, that MIGHT have had some affect, but NOT as much affect as going from dual exhaust to single exhaust (and one converter) where previous engines would have had real dual exhaust. There was one road test of a '75 small Fury with the 400/190 engine. The testers noted a drop in power above 4000rpm, which they attributed to the single catalytic converter and single exhaust. In general, their acceleration numbers were not nearly as good as I'd suspected they should have been. Later, they did a two-car test of a 440 Coronet police package and a civilian Coronet 400 4bbl. Numbers still seemed a little "weak", all things considered, as the internal specs hadn't changed that much, to me. Other thing was that these were the acknowledged TWO most powerful police packages in existence, back then.
ONE observation, in general, was that Chrysler's factory calibrations of TorqueFlite shift points was that they were a little low. This got them into "high gear" sooner, but at a detriment to road performance, by observation. Prior to the part-throttle downshift in about '71, this was especially noticeable in fast-moving traffic situations!
When we got our '66 Newport 383 2bbl, when the '67s came out, it was one year old and had 7100 miles on it. Compared to the prior 6-cylinder '61 BelAir, it was powerful as it was. I had the tuning finessed and was happy with it. Until . . . I took it to college in Lubbock, TX. I'd driven it in DFW metro traffic with no problems. But that time, I'd learned to do a manual 3-2 downshift at part-throttle to better merge into freeway traffic (mimicking the later part-throttle downshift), but out there, it was much more of a "stop light grand prix"! Normal throttle left me "in the dust" as the other cars roared off. More throttle didn't help, so I tried manually shifting the trans, which worked better.
After consulting with the old-line Chrysler service manager at home, I put two more turns of pre-load into the kickdown linkage at the carb. Worked MUCH better as it raised the shift points a few mph. Engine felt happier, too!
I test-drove a traded-in '85 Dodge 1/2 ton pickup we had. The 318 4bbl had equivalent power to the 305 4bbl pickups I'd been driving, so I wanted to compare them. The Dodge felt doggier as the trans upshifted too soon for best acceleration in part-throttle. WOT felt comparable, but part-throttle didn't. Manually upshifting helped a good bit.
Initially, I think it was more about smooth and torque-based acceleration until WOT was really needed. But as traffic speed patterns changed, so did the needs of the cars. WOT power was not always appropriate, but a part-throttle downshift (as GM and Ford automatics did) WAS a good fix. Yet, even then, the shift points were a little low. In later years, when the emissions specs were "grams/mile" rather than "parts per million", those lower shift points might have helped get them past the emissions testers, but did no favors in on-road driving situations. Moving the shift points up as I did with the kickdown linkage adjustment, meant "more acceleration with less throttle input", which made things feel much more efficient, to me. Wasn't "on the converter" nearly as much when the needed gear reduction was in the more efficient "gear" downshift orientation.
In a Newport with a 2.76 rear axle and H78-15 tires. The min-throttle upshift could be at about 27mph, which would have put the engine back at "idle speed" at that road speed. Any acceleration would have been "on the converter" in high gear. Works fine if you're not in a hurry. Generally too low of a road speed to really need WOT, too. A little more throttle in a Ford or GM automatic would have resulted in a downshift into 2nd and then later to 3rd as acceleration needs decreased. NOT until '71 for Chrysler, though. But even then, they still had shift point calibrations that were a little "conservative", by observation.
AND, as "exact" as the kickdown adjustments might need to be, that SMALL ALTERATION did NOT affect trans durability one iota! If anything, a "gear reduction" is less heat-generating than a "on the converter" acceleration where the torque converter slips MORE rattler than less.
Did similar things on my '80 Newport 360, but with a smaller black wire tie. They moved the kickdown road adjustment "under the car" to possibly lessen tampering desires?
More acceleration, less throttle, "happier" car . . . better feel and keeps the carb out of the power mixture. Win, WIN to me.
Just some thoughts,
CBODY67
