3927116AU smog pump pully question

[KevinW]

Hi all, I have two smog pump pulleys, both stamped 3927116AU, but one is stamped in a curve and one is stamped in a straight line.  I do not remember which pumps they came off, had two 69 pumps and two 71/72 pumps.

I need to put one on my 69 SS, so which one should I use, curved or straight? The straight one is a light stamping. thx

[z28z11]

Good question - I've seen both styles, have a '68 pump with a curved stamp, don't know if it's original or not, though, as it is a swap meet purchase. i do know that the 3935522 Z28 and HP BB pulleys for '68 were straight - all of them. Never seen a curved rendition for that pulley - and it's a '68 application, not '69 and later -

Regards,
Steve

[x66 714]

My original pulley doesn't have any letters, just the 3927116 part number & they are curved. The assm date on my 325hp car is 8/28/1969....Joe

[KevinW]

Thx!  Lets keep the example coming!

[firstgenaddict]

The 116's with the straight aligned numbers and the 2 digit alpha broadcast codes - are 70's.
 

[KevinW]

Thanks James!  My curved pully has the AU stamped after the numbers as well as a P at 6 o'clock. Still a pre 70s version? 

[z28z11]

Well, some yes, some no. I dug out 2 of the 116's I have in storage, the curved number shown is from a March '68 dated pump, the curved number AU suffix GM stamped pulley is still installed on a '70 dated pump. I'm beginning to think the straight line stampings may have been later than '70. Maybe need additional examples ?

Regards,
Steve

[KevinW]

Hmm, makes sense.  My later pumps were dated 71 for the 72 model year and must have had the straight version.  I will go ahead and use the curved version.  I hope it is not bent! Thanks all!

Have a set of grade 5 RBW pully bolts to use too.