First get the carb setup right so it will idle good with smaller jets, 2.5 power valve, then drill pvcr to make up for the smaller jets, may need a 50cc pump since you only have one, brown cam, bigger squirters. Should idle and respond good.
With a stock head at 15 psi you could make 400 HP but not with a stock pump and lines. 3/8 min. best 1/2 with a return to tank. you need about 32-36 gl/hr @ 22psi (6-8 psi plus 15psi turbo) most pumps are rated at free flow if you try to make pressure the flow go's away. A holley blue will not work, call any pump co. and tell them what you are doing (400+ HP and 15 # boost).
Ign. May need coil upgrade, new wires a must, NGK 6-7 heat range, 30-34* total timing, if ign. is weak a smaller plug gap will help .020.
I do not think you need an intercooler or water injection now just run racing gas when at high boost until you get everything right, it will be much easier and safer for now.
You are proving to all of us what I always thought, that a stock engine can take and make 400HP.
Turbos are easy on the bottom end, just need good pistons.
Harry
PS If you have only one o2 sensor you are taking an average of all 6 cyl and some may be rich and others lean so when everything is running good take it on the hwy. drive it for a few miles, then make a pass and read the plugs to see if they are the same, 400 HP is were you may have a problem with distribition.
