Supercharging: what boost can unmodified EG33 handle?

[vw1]

I am thinking seriously of putting a Lysholm-type blower on my engine, which is at present attached to a Porsche Turbo G50/50 trans in an 84 VW Caravelle, an unfinished project. I now have bought a 93 Microbus 2.5i with worn engine and will transfer the EG33/G50 into this and scrap the five-cylinder.

I do not intend to lift the heads of the EG33. Does anyone know what boost the stock engine can take? Would 10PSI lead to reliability problems? I believe that this engine has forged crank/rods/pistons as standard, though I haven't been able to confirm this.