alternator pulley

[Lee T.]

What size pulley is correct for the numbers correct alternator on my 69 350/350? My car is equiped with A/C, 4spd, w/out PS.
I've been told by Paragon, it should be a deep groove 3" pulley. The NCRS Tech Info Guide says, if I'm reading it correctly, a 2 3/4". Currently it has a 2 1/2".
I keep throwing belts (at or coming off high RPM's) and believe it's due to having to small of a pulley.

[Phil P.]

Re: alternator pulley

lee,if you find out that the pulley you have is correct,check the quality of your belt as most auto part stores sell off the shelf price competitive belts,but do have higher cost premium belts that streach less when hot and rpm'd---good luck,phil

[Joe L.]

Re: alternator pulley

Lee-----

The pulley that was SUPPOSED to have been installed for your application was of GM #1949356. This is a stamped steel type pulley of 2-5/8" OD. Usually, it will have a small "6" stamped on the outside face of the pulley.

In some case, however, I think that a GM #1949357 pulley may have been used for your application. This is an almost identical pulley except that it is 2-13/16" OD (i.e. 3/16" larger than the 1949356) and with a "7" stamped on the outer surface. The difference in size of the pullies slightly affects alternator drive speed but nothing else.

Regardless of which of the above pullies is installed, it should not affect the propensity of the car to "throw" the belt.

No 3" pulley, "deep groove" or otherwise, was ever used for your application.

Please check your pulley for the stamping I described and report what you find.

[Lee T.]

Re: alternator pulley

Thanks for your response Joe.
My pulley is 2 5/8" diameter, and does have a '6' stamped on the front face.

So, I suppose this is the correct pulley after all.

thanks

[Joe L.]

Re: alternator pulley

Lee-----

Yes, I would say that you definitely have the correct pulley. It's not only the one that's supposed to be there, it's also the one that IS there. So, the "stars are in alignment".