Originally Posted by marlinspike

Sure, but you don't need pushrods to do that with proper engineering. See the naturally aspirated Mercedes 6.2 liter making 464lb-ft or the boosted 6 liter making 738lb-ft (starting at 2000rpm).

Then again, why focus on horsepower? When building a car from the ground up I'll take horsepower with appropriate gearing...then again I'll take an independent rear suspension too.