I have a 72 472 deville. How can i get rid of this smog pump? Use washers to move the alt back..and run a belt around the crank alt and fan? Will that provide enough wrap around the fan?


It is an A/C car by the way.

The easiest way to do this is get a set of pulleys from a 425 engine that didn't have an air pump. Just be aware that your alternator will not be spinning as fast and may no longer keep up with your electrical demands at idle. This can be the case when the defogger, blower motor, lights and windshield wipers are on all at the same time. Another drawback of slowing the alternator speed is reduced cooling.

Didn't some years (1970 perhaps?) of the 472/500 not have a smog pump? Routing to that diagram and a few minor mods should allow bypass of the smog pump. Also IIRC on my 76 eldo with a 500, the belt to the alt ran the water pump as opposed to the belt to the smog. Routing to that scheme should work on any 472/500 albeit with some minor mods.

Besides, it is a PITA to tighten the smog belt running the water pump on a 68 472. If that could be rerouted to run water pump with the alt belt (I replaced stock gen with 1-wire alt) that would save a bunch of hassle.

If anyone has pictures from the shop manuals for either of those vehicles, please post.

The alternators are all mounted in the same plane. What gets changed is the crank pulley. The non air pump cars have a groove closer towards the crank for the alt belt and the waterpump pulley is different too. If you go to the older non-smog cars then you run into the 2 belt AC compressor setup. The later engines used 1. Maybe some commercial ones were different.

So I found a Cadillac with a 425. I dont know what year it is but the vin is

6B6958Q269395

It didnt not have a smog pump and had one belt for the a/c compressor i believe.

Will this setup work on my 72 472 to remove the smog pump? I need the crank pulley and waterpump/fan pulley correct? Is that all I need? Will this run the a/c and power steering pumps on my car with just one belt?


I need help guys :thepan:

The easiest way to do this is get a set of pulleys from a 425 engine that didn't have an air pump. Just be aware that your alternator will not be spinning as fast and may no longer keep up with your electrical demands at idle. This can be the case when the defogger, blower motor, lights and windshield wipers are on all at the same time. Another drawback of slowing the alternator speed is reduced cooling.

Is there any way to get around this?

Is there any way to get around this?

Some of the more modern alternators can make high Amperage at relatively low RPM. Dunno which. Try yours out first with the new belt setup and see it it falls on it's face with everything turned on at idle.