Gday guys and gals.

I just brought a 2002 HSV GTO coupe. In Mint condition.

I have had it about a month. When I brought it, it ran very smooth and quiet.

Last weekend we threw it on a dyno. (local guys to me here in Renmark SA with very good quility service.)
Mid run it missed and the mechanic shut it down. Turned out it threw a head gasket and filled number 6 and 8 with coolant!

After a strip down of the heads we found the steel layer head gaskets had been refitted with silicone! So it had obviously been apart before. I rang the guys who done most of the work on it for the previous owner but they never touched the heads. (they are a well know sponcer of this forum) so I trust they are telling me the truith.

The other thing we found was number 6 and 8 pistions had a chunk out of them. number 8 defiantly happend when it missed on the dyno we believe. Number 6 had been like it for ages!!! All carboned up and not a clear recent break.
So looks like the previous owner did a dogey. Cheers to him. Now I am up for a full engine rebuild! I gather I wouldnt have a leg to stand on. and its bad luck to me?

Its currently fairly standard. Genuine trutrac diff. Fully rebuilt 6 speed. Button Clutch etc.
Engine is stock. With bigger injectors (green top), Billit fuel rails and a raptor supercharger running 7psi (intercooled)

So because we are rebuilding it I am thinking of doing a few extra mods while we are in there. What suggestions do you have? What mods are good bang for buck?

I wont change the engine. Even if it costs more I dont care as I want the original engine in the car.

Cheers!