Quote:
Originally Posted by LET
Do these pulleys look Right? 67 GTO, I added a third pulley to the crank to accommodate Classic Auto Air.
Man, I sure hope they’re right!
Thanks
LET
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The factory V8 non AC crank pulleys weren't designed to add a 3rd pulley behind them. That will shift the original 2 groove non AC/PS crank pulley forwards aprox 3/32".
For V8 AC applications, Pontiac engineers always specified a larger diam crank pulley (usually 8" in diam) with a matching AC application pulley that varied from aprox 7" in diam, down to right under 6" in diam, this depended on the pulley series.
Non AC V8 applications used a specific crankshaft pulley, which depending on the pulley design series, ranged from around 6 1/4 to 6 1/2" in diam. These non AC crank pulleys were used in conjunction with a matching 8" diam water pump pulley.
Pontiac engineers revised the pulley designs over the years for various reasons.
For '67 V8 models they went to a slightly wider groove pulley. This was on all of the '67 V8 pulleys exc with standard steering (manual steering). When a '67 V8 was equipped with power steering, whether with just a 2 groove non AC pulley, or a smaller diam one to fit w factory AC, or one for CA use with the factory smog pump, the rear groove on the '67 wp pulley always lined up with the factory PS pump pulley. Of note, that particular PS pulley (either a "900" or "901") & PS pump setup continued to be used in conjunction w a '68 model one year timing cover (first to use a 4 bolt damper). Then that PS setup (first introduced for '67 models) continued to be used on '69 Pontiac V8's (4" hub height 11 bolt wp) & for the first 4 1/2" hub height 11 bolt wp which were first factory installed on all 70 model Pontiacs (except '70 V8 Firebirds).
For best engine cooling, its often easiast to replicate the '67 factory AC pulley set-up, that is esp the case if you desire to stick with the '66-67 V8 timing cover & 8 bolt stack type crank pulleys. If you can note the stamped numbers on your pulleys, can confirm what they are. Looking at the pics, the crank pulleys pictured are def non AC application. The wp pulley is not an "886" which is the smallest diam '67-68 wp pulley.
IF the original '67 timing cover has seen better days & an SFI rated 4 bolt damper & 4 bolt crank pulleys are in the mix, then it's time for a pulley conversion set which in your case would basically be '70 model AC diam wp &'crank pulleys along with a '69 model front alternator strap. Started CONVERSION sets together over 35 years ago when both AC usage pulleys needed were fairly common in our region. After decades of putting together countless such conversions, the problem over the last decade has been sourcing AC application wp pulleys. Typ the needed wp pulley is twice as expensive as the matching crank pulley.