[73ta]

I have put AC pulleys on my 73 455. I'm seeing a mismatch in the belt riding in the pulley grooves. I'm thinking this is causing an issue as they would be trying to go different speeds causing belt wear and noise. What do you think? Do I have incorrect belt width, or is my thinking off? Wider belt for PS pump?

[Mr. G]

Haven't seen a double grooved water pump pulley with different sizes before on a '73. The factory pulley would have been the same size on both grooves if I remember correctly. I think I have a factory one here near Reno if that is something you would be interested in.

[65 Lamnas]

Originally Posted by 73ta

I have put AC pulleys on my 73 455. I'm seeing a mismatch in the belt riding in the pulley grooves. I'm thinking this is causing an issue as they would be trying to go different speeds causing belt wear and noise. What do you think? Do I have incorrect belt width, or is my thinking off? Wider belt for PS pump?

Your WP pulley is incorrect….it should be a 481080. I think I have one somewhere if you’re interested.

[HWYSTR455]

Were the crank pulleys for those years one piece 3 groove for AC?

I know earlier ones were 2 piece, and not putting the 2nd pulley behind the 2 groove would throw stuff off.


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[73ta]

I have solved this. Another thread on here mentions that Pontiac used a wider belt for the PS pump. It appears that my double groove WP pulley and my double groove crank pulley, with the single groove pulley behind it, have a wider groove in them for the PS pump belt versus the Alt groove. Bought a wider series belt for the PS pump and now they ride at the same height. That will get rid of the belts trying to spin the pulley at different speeds making weird noises and causing wear. I don't remember where I sourced the AC pulleys, been too long ago, but I got them when I added factory air to my car and needed the faster speed for my water pump.

[73ta]

So I probably don't have 1973 pulleys. In looking at the catalog they used a wider, 1/2", power steering belt on some late 60's, early 70's 455's. 1968-1972 in hp motors.

[Mr. G]

Factory A/C pulleys diameter to outer edge are 6 1/2 inches for double groove water pump pulley. 8 inches for double groove crank pulley and approx 7 1/2 inches for single groove pulley behind crank pulley. I measured these on my '73 Formula with 455 and factory A/C. Just in case you wanted something to compare what is on your car with.

[73ta]

Originally Posted by Mr. G

Factory A/C pulleys diameter to outer edge are 6 1/2 inches for double groove water pump pulley. 8 inches for double groove crank pulley and approx 7 1/2 inches for single groove pulley behind crank pulley. I measured these on my '73 Formula with 455 and factory A/C. Just in case you wanted something to compare what is on your car with.

Thanks, my diameters match, pulley groove is bigger for the PS belt on my pulleys. Fixed it with a wider belt.