Ported intake on head - Good or bad?

[PSloan]

I've got a rebuilt cylinder head - and the intake has been hogged out quite a bit. Some say the smaller ports help to mix fuel and air so bigger ports are less efficent. True? I'm thinking since weber 38's run too rich anyhow this may help. Will be running a canon intake and header.

[monkeystripe]

I wouldnt say that a smaller intake port helps mix fuel, however, the casting marks that are removed in the porting process do help. there are two contradictory schools of thought when it comes to porting heads. First is that the sand casting bumps mix fuel and air better. The second is that smooth runnners flow better, causing a more linear charge, and thus more air fuel in each pump of the engine. So take your pick- better mixed ari fuel or larger charge, but not both. the heads for the m10 engine are fairly efficient th begin with. If you want to port the best thing to do is a intake match port, and then decrease the inside radius of the intake runnner and exhaust runner. Prety much stuff you can do yourself.

[Guest Anonymous]

You mean increase the inside radius dont you?

[PSloan]

I guess ill report back next week with my findings and some photos.

[robdelk]

gasket match the intake manifold and do the short turn radius in the head and the intake

[monkeystripe]

yes, I do. either way remove material...