turbo
You might want to look at a TA49 or the TA32. Both exceed your blocks capability. You will need the lowest ar on the ex housing for quick spool with the 5 spd and a blow off valve for keeping spool during gear changes. Following is from Precisions web site,link is on home page of this site............
TA series turbos include a new Billet aluminum inlet bell that eliminates the stock valve cover breather tube connection. This allows for the push-in style K&N filer in the passenger side valve cover. The stock adjustable wastegate actuator is a direct bolt, as is the stock or aftermarket downpipe.
STOCK APPEARING
Part No. HP Level Converter Performance
TA32 460 2,400 Min. Stall High 11-second
TA49 545 2,600 Min. Stall High 11-second
TA60 570 2,800 Min. Stall Mid 11-second
TA51 580 2,800 Min. Stall Low 11-second
TA52 590 2,900 Min. Stall High 10-second
TA53 600 3,000 Min. Stall Mid 10-second
TA54 610 3,000 Min. Stall Mid 10-second
TA63 670 3,200 Min. Stall Mid 10-second
TA64 680 3,300 Min. Stall Mid 10-second
Performance Turbochargers
If you're looking for a non-stock appearing turbo with all out performance the number one priority, these turbos are for you!. They fit all 1986-1987 Turbo Buick and 1989 Turbo TA's.
Most of the these turbos require an aftermarket torque converter with a higher stall rating than the stock converter to maintain proper spool up characteristics. These turbos will support 12-second street cars to low 9-second full out drag cars.
Most turbo models are available with both standard and heavy duty spring wastegate actuators. All models listed come standard with our PTE 3-bolt turbine housing in either .63 or .85 A/R ratios. Each turbo utilizes a custom adjustable wastegate actuator that has the correct bracket for true bolt-on compatibility. Actuators are available at extra cost
Buick Performance 3-bolt
Part No. HP Level Converter Performance Notes
TE32 480 2,400 Min. Stall Low 12-second Non-Stock
TE34 545 2,600 Min. Stall High 11-second Non-Stock
TE44 580 2,700 Min. Stall Mid 11-second Non-Stock
TE60 600 2,800 Min. Stall Mid 11-second Non-Stock
PT51 585 2,800 Min. Stall Low 11-second Quick Spool
PT52 600 2,900 Min. Stall High 10-second Quick Spool
PT53 610 3,000 Min. Stall Mid 10-second Quick Spool
PT54 620 3,000 Min. Stall Mid 10-second Quick Spool
PT61 675 3,200 Min. Stall Mid 10-second Quick Spool