So I'm considering getting some spare heads to get head work done on them and If anyone knows where i can get it done in perth (south of river if possible) would be a great help.

go see dave at RPW :doubt:
dunno any places mate but maybe ring around afew jap preformance shops
(cyhper, xspeed etc)

how much power you looking at making. STandard ralliart heads can flow up to 370hp so unless you are looking at somewhere up to or above that figure, then there is no point.

The Magna heads are over ported for the size of the engine. You could get more gains closing the bottom 1/3 of the port off to increase velocity into the combustion chamber.

Chisolm has some heads in the 4 sale section quite cheap if you dont have them as yet.
Regards

how much power you looking at making. Standard ralliart heads can flow up to 370hp so unless you are looking at somewhere up to or above that figure, then there is no point.


I'm gonna disagree here.

A bloke racing a magna in IPRA SA was running a near-stock ralliart motor early in his car's development. He found a 10-15wkw gain (can't remember exact number) from headwork on the motor without touching anything else. It seems even if everything else is left stock including the ralliart cams, there's stil healthy gains to be had correctly done headwork.

Correct being the operative word, as it's very easy to mess up the heads. You really need someone who knows what they are doing with them (i.e guys who are brilliant at doing old-school V8 heads won't necessarily have any idea about our heads).

And yes I'm selling a set of heads, complete with all valvetrain and in good nick :)

Screamin TE is right about the inlet ports being to big [wrong shape inside also],but Chisholm is right about more to be gained with the right work.I know the fella's that race them here and they tell me that there was plenty of testing with some good results, but only the deshrouding was done because it didn't cost any extra.

Here are some pictures of 6G74 heads and lower manifold. You can see inlet ports are filled and the combustion chamber cut back around the inlet valves. What you can't see is that the small twin inlet and exhaust ports have been ground out bigger. One picture of unmodified head shows how close the open inlet valve is to edge of the chamber wall and this blocks flow.