if you are going thru the hassle of installing a TurboBuick motor into anything get the best one they made that responds best to mods. The '86-87 intercooled GN engine/trans combo should be your only choice... get the same year tranny. Turbos and carbs rarely work well on a street car.... go with an EFI factory setup. The '84-85 "hot air" motors have a poor intake design and the turbo placement makes you scratch your head and they are non intercooled. These particular motors do not respond well to mods when compared to the '86-87 engine.
Nearly anyone can get the intercooled motor to go low 12's with about $500 in mods. Good exhaust, adjustable fuel pressure regulator, full tune up (plugs/wires/set sensors), stiffer valvesprings, race gas/high timing chip, traction, and a tuning device (ScanMaster, Turbolink, DirectScan). 300rwhp with the stock turbo is a breeze. Some guys are going high 11's with them.
Start with the lightest car possible and get free HP. 100lbs equals 10hp or 1 mph in the 1/4 mile.
The TH200-4R should always be used behind the GN engine and if you search you can find much discussion on reasons for this. Specific "BRF" valvebody and governor in the '86-87 GN trans allows shifts that are higher/crisper/firmer.
Of note: if you are installing this in a 3rd gen Fbody the GN engine is wider than the TTA (heads are different) and doesn't allow a/c to be retained as the strut towers are in the way. As long as you don't need a/c the GN engine will work fine. The TTA motor is much more difficult to source and has slightly different heads,headers, and a few other small differences.
-GNX7
