do you think my 150,000 mi ls could handle 5-7 psi, did a leak down test 7% leakage on 2 cylinders and 10% leakage on the other 2. my mechanic said those for very good numbers for the miles

 

You could but you won't be getting as much power compared to another turbo LS with 1% leakdown or something.

My advice would be to put in new piston rings..or just get pistons/rods/rings all at once while you have the block worked on.

 

Those are pretty good numbers for the mileage, but did you mention to your mechanic that you wanted to go turbo on the engine?

 

i got 129,000+ miles on my LS and im still boostin 5lbs. just be good to your car... dont over-do it and it should be fine. im pretty sure your leakdown tests are way better than mine. my engine has been abused. im going to need a new one soon. go for it... turbo is cool. your motor should be able to take it. provided that you tune it and maintain it daily.