blunce

I am looking for the exact measurement of what the propeller shaft (driveshaft) should be for a '69 2dr Cutlass w/ TH350. Using my '68 manual it specifies a "THM" for said car should be 55.1" but I forgot that the TH350 was not avail until '69. The measurement in the '68 manual is listed in the "Propeller Shaft" section 4A-1 in a chart at the end of that section.

Any help would be greatly appreciated since the correct driveshaft is all I need to drive my Cutlass for the first time since I've owned it (1yr).

Thanks!

joe_padavano

The TH350 driveshaft will be the same as for the Jetaway (ST300) in your 68 manual.

blunce

Thanks Joe!

So a driveshaft from a '68 2spd would also fit a '69 TH350 in a 2 dr? Length and spline?

'68 Chassis Manual lists the following:
F-85
Sedans or wagons - T.H.M. ------- 59.10"
Sedans or Wagons - M.T. or J.T. -- 60"
Coupes - T.H.M. ------------------ 55.10"
Coupes - M.T. or J.T. ------------- 56"
Vista Cruiser M.T. ----------------- 65.04"
Vista Cruiser T.H.M. --------------- 58.26"

I've been talking with a guy who has a driveshaft from a '68 Cutlass 2dr that had a 2spd trans and he measured the length center to center (of u-joints) and it measures 55" +/- 1/16th so I'm assuming he has the 55.10" driveshaft. Will that work or do I need the 56"?

joe_padavano

The manual trans, Jetaway, and TH350 all use the same driveshaft length. The shorter one may work, but you run the risk of too little engagement in the trans. Also, keep in mind that the different GM axles have different pinion flange to centerline dimensions, which also affects driveshaft length.