Would some of the guros be kind to take a look ad this porting design? :D

I'm just so insecure when it comes to this as I'm new to the porting world :)

EDIT, I'm am afraid that the edges of the 'D' will break into the water jacket... the edges are 22mm from the centrum, compared to the 15.5mm cirkel that it normally is :/

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You may add those photos to the Head Porting article -- just click Edit

YOU ARE A GODSEND! Just the pictures that I was looking for

They Just wasn't on the porting wiki and couldn't find them...

Thank you SO much!

Here are some old pictures that might give you an idea of what is inside and how thick the walls are.
This is an old A12 head that I cut in sections on a bandsaw.

http://datsun1200.com/modules/myalbum/photo.php?lid=10828&cid=12



http://datsun1200.com/modules/myalbum/photo.php?lid=10829&cid=12

Thanks for clearing that up ddgonzal!
Everything makes a lot more sens now
I see now how getting a A14 head is a no brainer, as it's not for a racecar but my daily, and me just wanting some more power ^_^

Quote:
this is how much





See Head Porting

Of course there are two types of porting:

* Porting for maximum HP. If your goal is maximum HP, better to get the best head to start with. The downside is that power shifts to high RPM (power at low RPM is reduced)

* Porting to maximum the head efficiency. By doing 1) Port Matching and 2) Bowl Cleanup you ensure the head is working well (and there is no downside, all RPM is improved)

A14 head won't lower compression. Most A14 heads are the same CCs as A12, although some later A12 & A14 heads (certain 1982 and newer) have a slightly larger chamber. See Chamber Size. In A12 engines, there are many piston dish sizes, which is primarily what determines compression ratio

All A14 heads come with the larger valves. All A12 heads have the smaller valves. By the time you add cost of new valves, and machine shop costs, it's usually better to obtain a good used A14 head. It's factory ported for larger flow already (80 HP vs 69 hp). Porting the A12 head makes sense when racing class rules don't allow head swaps, or when you are doing all the labor yourself

D shaped ports can work very well as long as they're not upside down.

Okay then.. Still some things to sort out;

1. A A14 head will lower compression. How will this hurt performance? Or does it counter for it by the bigger valves?
2. If I choose to stay with what I got, can my original question get answered, regarding how much and how i should port the head?

Rallytwit, installing larger valves require the head getting the seats maken bigger by a shop, and when it's there anyway, I might as well get it ported by them, right?

All aside I would also be keen to know what I can expect from doing this power wise ? :)

But have sent a PM to PJZ and is hearing him what he want for a head ^^