hey am looking at building up an ef head i know this has prob been covered but it would take me days to find the info i need just wondering im looking at port, polish and shave how much should i get taken off ?? and also does it really make a big difference eg if you take x amount of you are prob looking at x amount ok kw thanks guys cheers shoey

you have to work out what compression you need. that will determin how much need to be shaved off.

My general rule with the ones i do is to shave them until they are flat or 20thou wich ever comes second i'll also fit an AU gasket. that way there is no problem running on 95ron fuel.

if you need more compression shave it more.

IF YOU DO THE PORTS IT WILL GIVE YOU A BETTER AIR FLOW BUT YOU NEED TO MAKE SHORE THAT YOU GET THE IN LETS AND THE EX RIGHT IF THAY NOT YOU WILL NOT GET THE RIGHT FLOW YOU NEED

i had an EF XR6 head ported.. Super flow heads liverpool..
before= 305flow hp
after work done= 365 hp air flow test...

hardly seems worth it.

the guys that do the porting for me get a little over 500hp on a flow bench

they will remain namless as they dont like to deal direct to the public

500 hp??? what turbo are you going to use??!!

[quote="tickford_6
you have to work out what compression you need. that will determin how much need to be shaved off.

My general rule with the ones i do is to shave them until they are flat or 20thou wich ever comes second i'll also fit an AU gasket. that way there is no problem running on 95ron fuel.

if you need more compression shave it more.[/quote]

well whats a good comp rate?? does more comp mean more power??

i never said the engine was going to make that much power.
i said the the head could theoreticly flow enough air to produce 500hp
it's nothing new to quote head flow figures in HP





it depends one the cam you are going to use.
post up it's specs and i'll give you an idea on what would be best.
don't tell me what "stage" it is as that is no help at all

was looking at a wade 1636 cam

crikey thats some serious flow .
at what lift dose it flow 500 hp

with such a small cam you should have no problems at all with little to no increase in compression.

you get a small increase power and better fuel economy with higher comp.
max of 9.8:1 or you have problems with detonation. id recomend you stick with my previous post of flat or 20 thou witch ever comes second and an AU gasket. but make sure the head has not been shaved befor. if it has just get it flat again.

a 1521a could posibly benifit from 10:1 but would not be a must

i'm starting to sway away from wade to be honest. they only have one 'real cam' the 1521a every thing els is not really what i'd consider a proper upgrade.


crow do some nice cams

2222519 1200 4500rpm

2222543 1800 5500rpm

2222546 3000 6000rpm


the later 2 need a custom tune

sure cams

OXY48 1000 to 4000rpm

OXY35 2000 5500rpm

OZY2835 3000 6000rpm

again the later 2 need a custom tune

the 2 cams listed the have power from 1000 to 4000 would be in competition with the 1004 from wade and are all very small cams.

kind of shows you where the 1604 and 1636 site in the picture, even smaller again


none of them are worth putting with a high comp ported head they'll only let the head down.


if you want a worth while increase you 'll have to bit the bullet and get and aftermarket ECU

i'll have to check up on that .

there was an autospeed article that achieved a similare result with an AU head

oh righto i didnt realise it wasnt that good of a cam what do you think would be suitable considering im basically trying to get the most out of the top end as possible (without being to rediculous)

dont get me wrong thought there are other ways of doing things, it's just they are not the way i would do them.

give me a PM if you want to chat about it all or msn brad_man18@hotmail.com

If you do a really good job of porting and polishing the head, but leave a torquey can in the engine, you're doing yourself a dis-service.

There is one hell of a lot of physics that go into tuning and engine and getting power out of it which a lot of people don't realise.

Basically, the whole point of porting and polishing is to allow the engine to breathe better but the other thing you have to consider is air speed going into the engine.

To get good power out of an engine, you need to keep the gas speed as high as you can without restricting the flow. A low gas speed means you get poor cylinder fill and hence, poor power. If you do headwork to get more in the top end, you often decrease the gas speeds down low and get a reduction in torque.

So, if the cam's not going to produce power up top and you want to keep power down low, head work can often reduce your low down power and while it will allow the engine to produce more power up top, the cam won't allow that. So you end up with a very dissapointing result.

Also, increasing the compression ratio will only have a marginal difference if you're keeping a cam similar to stock. All it will mean is that you need to run a higher octane fuel. When you start getting into cams that have more of an overlap, you need a higher static compression ratio so that the dynamic compression ratio doesn't fall to low down low in the engine's RPM band.

So, if you want headwork to make the engine breather better up top, you have to put a cam in to allow the engine to breather better up top. If you do that, the stock ECU won't handle it and you'll need a programable ECU.

Now, if I have given any information here which is wrong, please feel free to correct me without flaming as all my knowledge comes from my own learning from experts, the net, magazines and a friend of mine who's spend 15 years on the V8 Supercar scene.