SB water pump shaft question
Thread Starter
Drifting
Joined: Mar 2011
Posts: 1,271
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From: PA
SB water pump shaft question
My pump has a 3/4" shaft. Do I need the same when I replace it ? All the ones I see have 5/8" shafts.....except for the one that cost 5x the price of a 5/8" pump. It has 3/4" shaft...
Race Director
Joined: May 2006
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Assuming everything else is stock you need a short pump with a 3/4 pilot to fit your fan and fan clutch. Where are you looking for the pump, have you tried any vendors from this site?
Last edited by MelWff; Feb 6, 2012 at 04:08 PM.
Drifting
Joined: Jul 2002
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From: The only Corvettes in Highett Victoria
There's a reason...............
The Corvettes also have a unique "length" water pump, so make sure you put your old pump down side by side with any new pump you intend to purchase and make sure it's the same.
Regards from Down Under.
aussiejohn
Thread Starter
Drifting
Joined: Mar 2011
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From: PA
They listed a normal pump at 30....an HP pump at 120. And some other pump listed as "P" for 80. All same base part number and part jockey could not tell me the difference.
Race Director
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Thread Starter
Drifting
Joined: Mar 2011
Posts: 1,271
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From: PA
Screw it. I got a 30 dollar remanufactured pump from napa. It's a GM housing. I'll roll this time and see what happens. It has the 3/4 shaft and the 5" snout.
Now tell me about those plugs/bosses on the tops of these pumps. What's that all about ?
Now tell me about those plugs/bosses on the tops of these pumps. What's that all about ?
Melting Slicks
Joined: Oct 2002
Posts: 2,317
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From: St Louis MO
There are 3 SBC water pumps for the Gen 1 engine - the short, the long and the Corvette short pump. As seen in previous posts, the corvette pump from '71-'82 is slightly longer than the short SBC pump (by about .150") and has a larger shaft (3/4") than the short pump which has a 5/8" shaft.
If you try to use a short SBC pump in a '71 or later corvette, you'll have belt alignment problems unless you use a pulley spacer (by about .150").
(See Noonie's later post, #19, with the exact numbers - difference is .175")
If you try to use a short SBC pump in a '71 or later corvette, you'll have belt alignment problems unless you use a pulley spacer (by about .150").
(See Noonie's later post, #19, with the exact numbers - difference is .175")
Last edited by larrywalk; Feb 7, 2012 at 09:46 PM. Reason: Referenced exact numbers
Melting Slicks
Joined: Oct 2002
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From: St Louis MO
The hole in the top of the pump is for a hot water bypass past the thermostat from the intake manifold. I prefer these even in engines without them because it helps to warm-up the engine evenly from both banks rather than only the passenger side bank (that's the bottom hole in the gasket on the pass side of the pump). If the bypass is not used, just use the plug to plug the top hole.
Thread Starter
Drifting
Joined: Mar 2011
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From: PA
Thanks that clears it up.
The one from napa is correct.....my old one is stamped "PH 406" and the new one is stamped "GM7".....any idea who made the old one. It's identical except for the plug on the top is a different size.
Also I'm confused about the Chevy tech article I read that says in 69 they went to long pumps. They have a window where they show two pumps and declare the long one to be 7". They go on to say these were used from 69 to 84. I have what they call a short pump then....? Mine is just under 6 inches...the old one and the new one. My car is 73. Shouldn't I have a long pump, pulleys, and brackets ?
The one from napa is correct.....my old one is stamped "PH 406" and the new one is stamped "GM7".....any idea who made the old one. It's identical except for the plug on the top is a different size.
Also I'm confused about the Chevy tech article I read that says in 69 they went to long pumps. They have a window where they show two pumps and declare the long one to be 7". They go on to say these were used from 69 to 84. I have what they call a short pump then....? Mine is just under 6 inches...the old one and the new one. My car is 73. Shouldn't I have a long pump, pulleys, and brackets ?
Last edited by boltnut; Feb 7, 2012 at 06:39 AM.
Le Mans Master
Joined: Sep 2001
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From: Unreconstructed, South Carolina
No sbc C3 came with a LONG pump. Only short OR vette.
Like Larry said above, there are 3 pumps available for Chevy sbc.
But, sbc C3 only had 2, short or vette.
If you mix one pump with another set of brackets-pulleys you WILL have belt misalignment & many headaches. (unless you correct with PIA shims, washers etc.)
Like Larry said above, there are 3 pumps available for Chevy sbc.
But, sbc C3 only had 2, short or vette.
If you mix one pump with another set of brackets-pulleys you WILL have belt misalignment & many headaches. (unless you correct with PIA shims, washers etc.)
Thread Starter
Drifting
Joined: Mar 2011
Posts: 1,271
Likes: 1
From: PA
No sbc C3 came with a LONG pump. Only short OR vette.
Like Larry said above, there are 3 pumps available for Chevy sbc.
But, sbc C3 only had 2, short or vette.
If you mix one pump with another set of brackets-pulleys you WILL have belt misalignment & many headaches. (unless you correct with PIA shims, washers etc.)
Like Larry said above, there are 3 pumps available for Chevy sbc.
But, sbc C3 only had 2, short or vette.
If you mix one pump with another set of brackets-pulleys you WILL have belt misalignment & many headaches. (unless you correct with PIA shims, washers etc.)
Race Director
Joined: Jul 2001
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Study pete74s diagram.
Race Director
Joined: Mar 2006
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From: Florida
Here are the specs I had for all vbelt sbc pumps
Small Block Corvette
1970 and earlier Corvette
5.625” Length Block face to hub face
.750” bearings
.625” shaft
1970 and earlier Severe Duty Corvette
5.625” Length Block face to hub face
.750” bearings
.750” shaft
1971 to 1982 Corvette
5.795” Length Block face to hub face
.750” bearings
.750” shaft
-------------------------------------------------------------
Traditional Short Pump
1968 and earlier passenger cars
1972 and earlier trucks
5.625” Length Block face to hub face
.625” shaft
Traditional Long Pump
1969 to 1986 passenger cars
1973 to 1983 trucks
6.932” Length Block face to hub face
.625” shaft
Small Block Corvette
1970 and earlier Corvette
5.625” Length Block face to hub face
.750” bearings
.625” shaft
1970 and earlier Severe Duty Corvette
5.625” Length Block face to hub face
.750” bearings
.750” shaft
1971 to 1982 Corvette
5.795” Length Block face to hub face
.750” bearings
.750” shaft
-------------------------------------------------------------
Traditional Short Pump
1968 and earlier passenger cars
1972 and earlier trucks
5.625” Length Block face to hub face
.625” shaft
Traditional Long Pump
1969 to 1986 passenger cars
1973 to 1983 trucks
6.932” Length Block face to hub face
.625” shaft
Thread Starter
Drifting
Joined: Mar 2011
Posts: 1,271
Likes: 1
From: PA
Thanks noonie. Do you know how those numbers apply to the different bosses on the top for bypass ? Were they on severe duty pumps ? Truck pumps ?
Here are the specs I had for all vbelt sbc pumps
Small Block Corvette
1970 and earlier Corvette
5.625” Length Block face to hub face
.750” bearings
.625” shaft
1970 and earlier Severe Duty Corvette
5.625” Length Block face to hub face
.750” bearings
.750” shaft
1971 to 1982 Corvette
5.795” Length Block face to hub face
.750” bearings
.750” shaft
-------------------------------------------------------------
Traditional Short Pump
1968 and earlier passenger cars
1972 and earlier trucks
5.625” Length Block face to hub face
.625” shaft
Traditional Long Pump
1969 to 1986 passenger cars
1973 to 1983 trucks
6.932” Length Block face to hub face
.625” shaft
Small Block Corvette
1970 and earlier Corvette
5.625” Length Block face to hub face
.750” bearings
.625” shaft
1970 and earlier Severe Duty Corvette
5.625” Length Block face to hub face
.750” bearings
.750” shaft
1971 to 1982 Corvette
5.795” Length Block face to hub face
.750” bearings
.750” shaft
-------------------------------------------------------------
Traditional Short Pump
1968 and earlier passenger cars
1972 and earlier trucks
5.625” Length Block face to hub face
.625” shaft
Traditional Long Pump
1969 to 1986 passenger cars
1973 to 1983 trucks
6.932” Length Block face to hub face
.625” shaft