Water Pump

It all depends on what you have for a water pump. There are long ones and short ones. I’m talking about snout lengths. Again, no electricity here so can’t really look up stuff. If you have the 87 pulley setup with ac then you need a pump for an 87 307 with ac. If you got the old 69 pulley setup you need a pump for your 69 applications if you have ac or no ac. That’s about the best I can do from memory and the fact I’ve got about 12 things going on atm.

This may help. Ac pumps are 5.572”. Non-ac are closer to 5”.

Here's an excerpt from my build thread, where I recently replaced the pump on a bone stock 1978 Cutlass equipped with a factory 305 Chevy with A/C on the driver's side. Long water pump, V-Belt setup:

"I elected to continue on with my factory performance upgrades and chose a Heavy Duty Aluminum pump listed for an '85 TA, K5 Blazers, and other vehicles known to be abused. Heavy duty water pumps aren't really anything special since every engine with A/C had them, but this one is special since the impeller is way better than any other pump I've disassembled. Heavy Duty essentially means that they've employed better bearings and impellers, and might have cleaner flow paths free of casting flash and large irregularities. I chose a Duralast CWP520HDA ($70) but the same exact pump is sold as 1121HX and 20040HX as a stock replacement. It's also the same pump offered by Airtex (the maker), CVF Racing, DeMotor, Speedway, etc., some of which charge over $200. As long as you see the "X" or "A" alongside the number it's the same pump. Same. Freaking. Pump. This is proven by searching by the number stamped on the housing: GMB 130-1250HP.




Now this water pump came with gaskets but they're a cork/rubber amalgam that I just know will be difficult to remove later so I had even better ones on hand. Say hello to reusable water pump gaskets from SCE, # 21101. I've employed them before and yes, you can absolutely use them multiple times without sealant of any kind."




•Check the airflow through that radiator: you may need to replace missing pieces meant to direct the air, and make sure your lower front air deflector is present. It creates a low pressure area behind the radiator that invites the air to flow through.

I've had a Stewart/EMP aluminum stage 2 pump in mine for quite awhile, gotta be close to 10yrs, no problems at all. Mine's a serpentine setup, (80's F Body TPI) so it's CCR (Counter Clockwise Rotation) so you would have to make sure you're getting the proper rotation for your application.

I've seen people put a CR pump on a serpentine system, and had it cause some problems but usually it doesn't happen the other way around.

I agree with what's been said that a stock (A/C or HD spec'ced) pump will likely be perfectly fine unless you're really making a lot of HP, and heat.

Out of curiosity, what thermostat did you use? Did you go stock replacement, or did you go colder?

Was it running hot and then you did the thermo and rad replacement, or did you do the swap and then it started running hot?

Hutch

Crap. I thought you meant a real 350. Not the wannabe Chevy 350 🙂 Forget all that stuff I mentioned about Olds water pumps.