To add further to what TOMS86GN said, 83#ers are overkill for sure, when you can successfully run into the low 10's easily with a set of 65# (60) Mototron injectors and still get a good chip and have good gas mileage with the factory ECM. Especially if you add an alky kit to the car.
Now, as far as 10.50's reliably, I personally would go with a PT6776H turbo. This turbo will support up to 785 fwhp and needs a converter that can flash stall to 3400-3500 to spool up well. This turbo is also available with dual ball bearings and would require less stall converter. (Model # PT6776RH) Typically a converter that could flash to around 3000-3200 would be nice. Either version (non bb or dual bb) will easily push a full weight Buick with all of the other supporting mods (cam, heads, intake, IC, fuel system, exhaust, tranny, converter, suspension, sticky tires) into the mid 10's at around 23-28psi. Aluminum heads and a roller cam would be in the 23-25psi range, iron heads and flat tappet cam would need 25-28psi range. If more of a street car, either model will be more responsive with the .63 A/R 3-bolt turbine housing, but if looking to get the most out of a combination, then choose the .85 A/R 3-bolt housing. I know if I ever build another street driven 10 second car, it will have this turbo on it. It is an awesome turbo. There are others who will say TE45, TE45a, T63E and T64E but this turbo will out perform them all.
Just my O2's worth.
Patrick
