as per spuddy, we would need to what turbo you are running, as 1.5bar on a ct9 and 1.5bar on a t51 for example would bea savage difference. Another factor would be the compression ratio/depth head gasket/low comp pistons? As you'll find thinner metal gaskets will just pass over as the head lifts given the large boos figure.
Any chance of a full spec?
Regards
al