20% Under on a Small Block Chevy Water Pump???

[no74falcon]

I'm trying to decide on a set of pulleys for my vintage Mod and was wondering if I wanted to try a set with a 20% reduction. What advantages would I get, other than slowing down the pump, which increases horsepower, so they say. My preference is to make sure it runs cool, as opposed to gaining a few h.p. Should I just run the standard 1:1 pulleys? The underdrive set seems to be cheaper from Speedway Motors. I should add that the engine is a stock build reman. 350. Thanks!

 

[spooker]

Allen, I ran a dirt late model from 1977 to 1982, ran a 327, turned it 6600-6700, ran stock pulleys for the water pump, never had a problem.  Used flow restrictors to fine-tune things.  If you aren't going to twist your mod engine any higher I wouldn't worry about it (if you have stock pulleys lying around).  I DID have to reduce the rpm of the steering pump, however.  HTH!

Brian

 

[no74falcon]

Thanks Brian! We are just gonna go play with the Midstate club. No pressure on winning or anything like that. I've had this car for a few years, and finally found a worthy cause. Not sure if you are familiar with Sam Carista, but he was racing at Fulton back in the 60's when my dad first started. Well, all these years later, Sam's great granddaughter, who is 16, has been getting her feet wet in karts and recently moved up to 4 cyl. at Brewerton. I want to give her an opportunity to drive a bigger car before she steps up to Sportsman. We just wanna have fun!

 

[spooker]

Sounds good to me!  I'll be driving a Midstate car (not mine, it's coming along REAL slow!) later this summer, late July I hope.  See you at the track!

Brian

 

[joebiv318]

I will add to this for anyone else who my look at this topic...

Most cheaper (stockish) water pumps have a bushing and can only handle around 5000-5500 rpm.
Most racing rated water pumps have a bearing and can handle higher sustained rpm, say around 7000 or so.
Most STOCK pulleys are OVER driven (smaller pulley on pump) this is to speed up the pump while tooling around town at 2000 rpm, the water pump will be turning faster.
UNDER driven pulleys will have a larger pulley on the pump to help slow down the rpms or free up some power.

So I would think you need to see what type of water pump you have, what rpm range you will be running in and what rpm you want the water pump turning...

 

[uticamike]

When is the 74 Falcon gonna fly?