[65madgoat]

Can anyone confirm the correct 2 groove water pump pully used on 1971-1972 455HO cars ?

Was it the 481040 XT pulley used on all other V8 of the era or did it have a different part number?

[Kenth]

HTH.
Right click, save and turn to read.

['ol Pinion head]

The above charts echo the assembly plant practices that I've encountered. that's not always the case!

Only the '72 automatic Firebirds w 455 HO & factory AC, used the smaller diam 485397 pulley.
My '72 M22 T/A has factory AC, & uses the slightly larger diam 481040 (normal diam 71+ AC) wp pulley. The reason for smaller diam WP pulley in the T400 AC application comes down to dealing with disipating the extra heat in the 2nd Gen Bird installation. 2" narrower length radiator than an A-body, as well as that radiator only being a 3 core for '72 AC applications. By '73, the 4 core rad was back in use in performance AC Bird applications.

Have a large supply of clean straight rustfree Pontiac V8 water pump & crank pulleys,
running out of 485397's, but have a few left.

[hiyabradHO]

Originally Posted by 'ol Pinion head

The above charts echo the assembly plant practices that I've encountered. that's not always the case!

Only the '72 automatic Firebirds w 455 HO & factory AC, used the smaller diam 485397 pulley.
My '72 M22 T/A has factory AC, & uses the slightly larger diam 481040 (normal diam 71+ AC) wp pulley. The reason for smaller diam WP pulley in the T400 AC application comes down to dealing with disipating the extra heat in the 2nd Gen Bird installation. 2" narrower length radiator than an A-body, as well as that radiator only being a 3 core for '72 AC applications. By '73, the 4 core rad was back in use in performance AC Bird applications.

Have a large supply of clean straight rustfree Pontiac V8 water pump & crank pulleys,
running out of 485397's, but have a few left.

Roger, Do both the 485397 and the 481040 have the same exact offsets of how the two pulley grooves line up when installed (relative to say the 80 AMP alternator's pulley groove? Also, do the two pulley grooves on the 485397 and the 481040 have the same spacing between the two grooves? Thanks, Brad

['ol Pinion head]

Both have exact same offset & spacing, designed to be used with 55 amp alts or the 80 apps.
Will take some pics.

[65madgoat]

[QUOTE='ol Pinion head
Have a large supply of clean straight rustfree Pontiac V8 water pump & crank pulleys,
running out of 485397's, but have a few left.[/QUOTE]


Would like to buy one of your 485397 pulleys. Thanks. PM sent.

[65madgoat]

Does anyone know if Pontiac used different V-belt sizes due to the smaller water pump pulley used on auto/AC 1972 Trans Ams?

['ol Pinion head]

The front & rear grooves of the 3 different '71-77 Pontiac v8 pulleys are the same width & same depth. Same series of pulleys.

When one goes back to the '70 ONLY A-B-G series model Pontiac V8 water pump pulleys, the front pulley groove is narrower & the rear groove is wider than the '71+ Series pulleys.

Dropped you an email a few mins ago, Roger

['ol Pinion head]

just got in for the evening. cked in my '72 dated Master Parts book, alternator belt is 1/2" shorter with the smaller diam 485397 pulley