...
71 was also an odd year for the 383 because the horsepower ratings took a nose dive and there are a number of small differences. Of course 71 was the final year for them as they disappeared to be replaced by the 400 starting in 72....
Everything took a dump in 71-72, it was the first year NET HP was quoted, ie. with full dress accessories, exhaust and rear wheel measurement. 71 was also a smog year too
"..in 1971 Chrysler published both gross and net HP figures for all of their engines across the board. The most common 440 V8 in their full-size cars was rated 335 gross and 220 net. That's pretty extreme, though... usually it's more like 10-20% lower. There's no reliable conversion because of huge variations in gross testing and reporting methods.."
