Hey Mate!
Haven't heard from you in ages! How did that 1200 flywheel go ?? Hope it helped. I'm keen to see the 1200 now!

Yep. theres many chamber shapes (see the tech section). Why don't you pop in and see me some time. There's much to talk about and i might be able to help you in other ways too! Send me a PM if you wanna chat.
Daniel.

Quote:

Not sure about Aussie or USA but in NZ all the A15 heads I've seen have had the closed kidney shaped chambers. Don't know the standard CC, may be more than A12 I would guess but after planing my chambers were around the 29cc mark from memory.

the a-14 "gx" cyl. head has a 29cc combustion chamber, 35mm int. and 29mm ex. valves, and oval ports. also has tapped holes for both 1200 intake(center bolt) and 14/1500 intake("ear"bolts) manifolds!
but... thier are big chamber oval port, small chamber round port, etc. etc. don't even start with nismo!

There are different A14 heads. I've seen both the large oval port heads (open chamber) and the small oval port heads. The Nissan book also shows a round-port head on the 5-speed B210s.

Correct me if i'm wrong here, but doesn't the A14 head have the same valves as the A15, oval ports & a smaller conbustion chamber?
If so, then this might be a better proposition to start with.

Agreed, it would be practically impossible to bring a standard A12 round port head "up to A15 spec".

On the other hand, it's difficult to bring an open-chamber A15 head up to the closed-chamber design of the early A12 head. It would take a lot of aluminum welding.

What is your goal?

You will have a lot less grief, & save yourself some cash if you start with an A15 head in the first place as it will have the oval ports already & come with the 30mm exhaust & 37mm inlet valves as standard.
You may need to shave the head a little to restore compression, & if it is going onto a 1200 engine, you will need to cary out a small mod to ensure that oil gets to the rockers as this part differed between the earlier & later engines.

You will not successfully port a round-port head out to the oval-port size & shape, at least, not cheaply.

CAN ANYONE TELL ME WHAT I HAVE TO DO TO BRING MY 1200 HEAD TO 1500 SPEC WHAT SIZE VALVES ECT ECT