Was lucky enough to get my hands on a cylinder head which had been gas flowed by NZ's top Toyota Guru, Lynn Rogers courtesy of AnthonyM. It had been previously used in an MR2 which had a dyno proven 450bhp. Head was 10,000kms old and came complete with HKS 264 cams.
It is actually from a 3S-GE motor which Toyota originally fitted in their factory to an Altezza. When I got my mitts on it, I sent it to a local head specialist who cleaned it up and pressure tested it. New valve seals were installed, valves re-seated and uprated valve springs fitted due to the rev limit being increased to 8,000rpm.
There are a few minor differences between the n/a and turbo heads which meant a couple of bits of creative engineering were required.
The GT4 uses an EGR (Exhaust Gas Recycle) system as part of its emission control which requires a slightly different valve cover. As a result, a small piece of ally needed to be welded between #4 spark plug hole and the end (as can be seen in the photo below). Otherwise there would be a gap for the oil to splash out. This is due to the EGR 'feed' being at this end on the turbo head.
Also, the 3SGE uses top feed injectors as opposed to the larger side feed on the 3SGTE. So the injector holes needed to be re-drilled to accept the larger injector nozzles.
A fair bit of work has been done on the inlet and exhaust ports to improve flow as can be seen in the next two pics...
As well as increasing power, should also reduce lag quite a bit too
Also, decided to 'tart' up the alternator too being as it is in such a prominent position. So it was stripped right down to its single components...
While it was apart, new bearings were also fitted.
And the finished article..
Amazing what a bit of chrome can do if it's applied in the right way
Gary