So, I'm reading that the stock horsepower from a '78 400 was either 180hp or 220hp.... is that fact ?
That just seems really, really low.. Even by 1970's standards.
I guess it depends on what you're comparing the hp numbers to. You may already know this, but engine hp ratings were higher before 1972, because the way horsepower was measured was different than the way horsepower was measured after 1971. Before 72, the ratings were gross hp. 72 and later, the ratings were net hp ratings, which is a lower number. So, for example, there was a year or two there where the exact same engines went from like 400 hp to 250 hp in advertised ratings, with no actual change in the engines. So, 60's to 1971 engines weren't always really as high horsepower as they were sometimes advertised, and the 70's engine weren't always as low as they were advertised. In other words, the differences in horsepower wasn't as great as it seemed by the numbers, because the numbers were arrived at using different ways of measuring. Although with lower compression and emissions equipment in the 70's, the power did go down, not just in the way it was rated. But the difference in the rating method was a big part of the lower numbers. Of course, the lack of acceleration in the 70's was also related to the 2 series rearend ratios that were used in a lot of the cars from 75 and later to get better gas mileage, while eariler cars usually had lower rear gears(higher numerically) for better acceleration.
This is a link to a page that explains it much more thoroughly and better than I can:
http://ateupwithmotor.com/automotive-terms/47-gross-versus-net-horsepower.html