Horsepower Rating Change 1971 to 1972

[Brian Monticello]

Hello,
The link listed below has a collection of quarter mile times and displacement/H.P. ratings for corvettes from each year until '78. Its difficult to compare apples to apples using these numbers because of the differences in gear ratios and the omission of transmission type, etc....

http://www.corvette-101.com/perf.htm

What were the changes in the Horsepower metric that chaned from 1971 to 1972? How would a '63 327/300 stack up against a '74 350/250 on a dyno?

Thanks,
Brian

[Ed Jennings]

Re: Horsepower Rating Change 1971 to 1972

I think I have seen this figure pegged at about 25-30%, ie an engine rated at 300 gross hp might be rated at 220-225 net hp with no other change. There is not a direct ratio between gross and net hp figures, since the accessory load and exhaust restrictions will affect different engines somewhat differently.

[Patrick H.]

Re: Horsepower Rating Change 1971 to 1972

Brian,

In addition, the motors in 1972 Corvettes were virtually the same as those in 1971 Corvettes. That should help give you an idea of how much the ratings change affected the listed horsepower.

Patrick

[Duke W.]

Re: Horsepower Rating Change 1971 to 1972

Interesting to note that the quarter mile performance for the base '75 automatic, which represented the low point of emissions era net power was about the same as the '55 V-8, which is about the same as a modern two-liter compact sedan with a manual transmission!!!

Duke