Big Block Chevy questions- rectangle or oval port?

[maddog]

I have dumped the flathead Ford stuff (no disrespect intended) and I am focusing on the Fiat and its BBC.

I have some options as far as rectangle vs oval port heads and intake.

What is the deal with this?

Thanks in advance.

 

[Gastrick]

Well the rectangle port heads are the biggest and will offer the most flow in all out high performance applications. But all in all, a lot of folks prefer the oval port heads for street cars because of better low/mid rpm characteristics. Unless you are making a lot of power or running a really big inch engine. The oval ports are fine. The rectangular ports, or square ports as they are sometimes called, are better all out performers. That's the way I see it anyway. I've run both, but I'm not a professional engine builder by any stretch.

As a side note, there are also round port heads that were generally used on trucks. Stay away from those. They don't breathe well.

 

[gassersgarage]

Some say the rectangular port heads are too big for street use. I've run both and both ran fine for its intended purpose. My Vette had the big heads with a lot of port work but I was running a roller cam and 4:88 gears. My Biscayne had the oval ports with a hydraulic cam and still handled over 500 hp.