Why do.....

[SSR]

........ Old American cylinder heads have rectangular section ports?

Makes no sense to me coming from the UK with nice round section ports......

Just wondered.

[jfholm]

A lot of it is due to packaging limitations. I think it may be easier to package the head with rectangular ports to get the required volume for the bigger V8 engines. We know that if we take and rectangular port and round the corners as much as possible you get more and better flow. I remember flowing a set of heads a friend of mine had done for his Small Block Chevy NHRA Super Stocker. It was right after they allowed porting of the heads. These heads had been made very oval shape by brazing inside the ports. The port surface was also just the stippled carbide burr finish, (which is the way I leave my personal heads). The were killer heads for stock 461 casting. They flowed all the way to .850" lift. They also cost around $5500.

John