How many horsepower does the stock Pontiac 400 Big Block have?

Answer 1

Depends GREATLY on the year of manufacture, and if it was a high or low performance motor from the factory. The highest production motor was the 1969-1970 high compression Ram Air IV at an underrated 370hp @ 5500rpm. Later (after 1974) smog motor 400 4bbl motors were 180-220hp. There were even 2bbl economy 400's that were rated at 170hp. There was also the over the parts counter Ram Air V crate engine in 1969-1970. It had no offical factory HP rating, but close to stock Royal Pontiac tuned test cars back in the day ran 11.60-11.80's at 116-120 mph, suggesting an actual output somewhere over of 500hp. Less than 200 were produced and go for huge money today (like $10k for a set of heads and $5-6K for an intake!)