Vuaxhall 20seh build

Hi kan any one assist on forums and info we setting to build an vuaxhall engine code 20seh it an 2l 8v engine and need info as to wat best route Wil be as we want to stay normal aspirated and looking for an fig of round 150hp

That's not an engine I've had anything to do with unfortunately. Your best bet would be to look for some enthusiast forums that deal with this engine to see what others are doing. A quick google shows that the SEH is around 127-130 ps in stock form so you're not a mile away from your target. The normal path I'd take would be to increase compression (fuel dependent), source a camshaft with a more aggressive profile and potentially you may need to have the head ported to flow better. Add a proper exhaust and intake and tune it properly and I'd think you should be able to make your target power.