Especially back in the old days, the cylinder heads were the main restriction when it came to making horsepower.

Most stock heads did well to properly feed small engines... let alone larger ones. Larger engines would be 'wheezing out' by the time they hit very many rpms.

If you needed more top end than low end... which was the case for most with the crappy tires and suspensions of the day, you could de-stroke an engine and trade off some of that unneeded low end grunt for top end horsepower!

I top-end raced a 421ci small block Camaro on the interstate once (no bottle). We were close at first, but his big inch motor started to wheeze out of cylinder head around 130mph... and I was able to walk right past him. He was pissed and confused, and his friends made fun of him. [img]/phpBB/images/smiles/icon_smile.gif[/img]

I don't do that stuff anymore.
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