I was thinking the other day about engine options for the coupe and something that sounds simple enough got me really thinking. Can an oval port head be drilled and ported to become a round port? also can a low compression head be welded and reshaped to become a high compression head?

The oval port can not be reshaped as the hole is too large. Why would you want to do that?

the oval port IS the round port elongated (so-to-speak)

Cool, more online people. Well basiclly I was thinking about the charactersistics of the types of heads, the lower rpm efficient oval ports and the higher rpm efficient round ports. Plus if it's achievable at an alright price it might be somewhat of an equal to that ultra rare A12 Race head, the one with the almighty inlet ports I've seen somewhere on this site before.

I think this quote says a lot....as does the webpage it comes from (see link)

The single biggest factor that determines an engine's ultimate power potential is the total inlet valve area

http://www.pumaracing.co.uk/pp01.htm

Quote:For the Datsun A engine, no because there is not enough metal on the sides of the port to grind it out that big.

Quote:Yes, this is not unheard of.

Quote:In general, yes a round port is good. However, on the A engine, the round ports (28x28mm) are small, hence good for lower RPM, while the oval ports (28x34) are larger, hence better for high rpm.

A 34x34 round port would be better for high RPM than a 28x34 oval. But it's not a choice we have.

Interesting read that was. Ok then, to what extent can an oval port head be widened to? 2mm? or would that be too much?