N42 head porting question

[cpark_12]

I've got an N42 head that I'm putting on my 83na.  My question is, can I open the exhaust ports up a little?  I have a set of round headers and, of course, the exhaust ports on the head are square.  Can I port them and polish them up a little with no worries of eating into anything else?

[Kurbycar32]

I asked a similar question regarding putting a round port header on my square port N42 head.  The consensus was that you can go the other way, mounting a square port header on a round port head, but not the other way around.  You need to sell or trade your round port header and get a square one, on the plus side the N42 seems to be the most desirable head choice. 

[johnc]

There's no reason to put any effort into making the head flow better when you're going to screw that all up by installing a round port header.

[Xnke]

Not that a roundport header is a bad thing; more that the port shapes need to match up or you will have some issues. Namely, keeping the manifold gaskets sealed up. The round port header on a squareport head has problems with burning out the gasket, as well as heavily compromised flow through the interface. Squareport headers used on roundport heads have less compromise, but are still far from ideal.

 

Just trade out for a squareport header and save yourself a lot of time, headache, and possible damage.

[Tony D]

Use the proper gasket, no head work necessary.