Input Shaft Diameter?

[quickster]

Does anyone know what the input shaft diameter is, of the steering rack, on a Pontiac Grand Prix GT 3800 Series 3? I'm looking at two steering racks from NAPA. The NRP 221025 has an 11/16" input shaft, and the NRP 221023 has a 5/8" input shaft. I want to have the right one ready to go in as soon as I remove the old one. Thanks.

[BillBoost37]

never heard of that... Please keep us up to speed on what you find.

[quickster]

NAPA auto parts refers to it as "input shaft". Maybe "output shaft"? I"m thinking it's the size of the shaft of the steering rack that connects to the steering column. Just hoping someone here might know.