I saw that my head is an h74 and my friends one is an h89 with heart shaped combusrion chamber..so definetly going to buy that one and send it in for gasflow and to fit double valve spring..can anyone mabye tell me what the valve clearance should be when fitting the new head?

I live in gauteng area..you near from me ?

PJ where do you stay in RSA north or south. If you in the south you can check mine out and i can give you the name of the chap that did my motor. Almost 100kw and lots more can be done or just phone me [shaun 0824857669]

It's not going to beat the 2 liter cars.

To ID the head ... remove the rocker cover and note the casting numbers. There are likely two numbers.

I'm not sure on the head type..but it's from a 2006 nissan champ if that helps?,how can i check what head it is? ..and yes sorry they are dceo40's..only planning on spending bout' 12gran(south african rand) on the motor..but the gx head and cam sounds like a good idea..?as long as i can beat my friends with their 2.0 and 1.8 stock golfs then i'm happy

Good topic. I'm about to rebuild my A15. It's got the H89 head and I will be using 40mm twin dellortos

Whoops was my phone. My bad. I meant to say that from past experience and reading worked A series engines can happily rev out to 9 grand (more so speedway motors...)

Quote:What?

I've always found and read a motorsove high comp and can rev out to 9 grand... This whole engine depends on how far and how much money you want to invest into the project. Don't get me wrong it a lot o money but the finished product is near always awesome and sounds great with some extractors and decent exhaust!! The weber induction noise is a unique sound by itself I love it!!

Yes, all true that. Certainly fitting 79 mm pistons will return far more HP than shaving the head and double-valve springs -- or even changing the camshaft.

Note that H75 and H89 can both have the same compression ratio depending on the year/region of the H75 (there are many H75 heads). For best power and fuel economy go with a closed chamber head. Control your compression ratio with the piston dish -- using flat-tops to raise compression often results in better power than milling the head.