[68ragtop]

Originally Posted by kk68

Meant to respond to this awhile back. Took the attached pic from mine and measured the visible fan clutch shaft between pulley and fan at 1.5 inches.

Which clutch is that? Thats one of the longest ones I have seen! I'll be that tucks the blades into he shroud decently.

[north]

Looking at my nov 69 MPC the clutch situation is interesting-confusing...

1967
Very complicated listing of 5 different clutch numbers. Two of them carry into 68 (PD, PG)

1968
F8 w/AC
GTO w/AC 9792938 (no letter code)
T8 350 and all P8 w/AC 9790972 (PG)
All V8 9786404 (PD)
I think the PD was used on non AC applications as it appears in 67 and was only listed for non AC applications

1969
All V8 w/AC 9792938
This is the only clutch listed for 69, no letter code listed and no non AC mention

1970
477957 all V8 w/AC or with Thermo Fan
The only listing for 70

I don’t believe they changed the clutch for the water pump length change in mid 69. If they did they’d have to list early and late. Also the 69 Firebird ran the short pump right till the end in nov 69, one full year after the rest of the Pontiacs switched.

Btw the bolts to bolt the clutch to the pump are listed for 61-69. No mention of 70. Did they switch to studs in 1970? Or did they just not update the listing to include 70?

[TXSTARFIRE]

9792938 is code PH.

[73ta]

Originally Posted by kk68

Meant to respond to this awhile back. Took the attached pic from mine and measured the visible fan clutch shaft between pulley and fan at 1.5 inches.

Your belts are riding at different heights on your pulley making them try to spin it at different speeds. I went thru this on my 73 TA. Had to get a wider belt so they ride at the same height.