does anybody know the reason for the different horsepower ratings on slant sixes across different years? i was looking at the slant six article on allpar.com, about halfway down the page in the "all in the slant six engine family" section they break down the compression ratios, hp, and torque ratings for each engine size over time. the ratings drop off after '71. i'm wondering 'cause i'm looking to get a 225 to replace the 170 in my '65 valiant and it's tough to find one that's even pre '75.

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1965 Plymouth Valiant v100

One of several search results using the terms gross net horsepower rating: http://www.slantsix.org/forum/viewtopic ... ting#71614

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Joshua

aha! i knew there had to be something on here. this place is just full of info. it had to be something with the search terms. thanks a lot dude!

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1965 Plymouth Valiant v100

"There wasn't a significant power drop in 1972 when the 225's rating went from 145 to 115. The significant difference was in the rating system, which changed from SAE Gross Brake Horsepower (engine minus alternator, exhaust system, air cleaner, and other power-using accessories) to the more realistic SAE Net Horsepower (engine as installed in the car)." - Slant Six Dan.

See here and here.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

And on my race car I am between 275 rwhp and 300.Depends on weight and hook up.I love beating V8 cars and tell them I got under 300 hp.Guzzi Mark