Water Pump shaft diameter

[billybob]

Quick general question,

On years leading up to 70 the pump shaft for a small block was 5/8" then 71-82 it went to 3/4"

The question is why?

Bill

 

[billybob]

ttt

 

[billybob]

Still looking for an answer.. the reason is that I have a new stage 3 stewart water pump (new that I got cheap) that I want to use it, but after doing a bit of research I see its different only by the shaft diameter.

So do I buy another or am I good to go???

;help

Bill

 

[ccflorida]

Stewart Pump

Bill,
Why don't you call Jack Wilson at Stewart? His number is (336) 859-2555. I found him to be very helpful..

 

[Jack]

Re: Stewart Pump

Bill,
Why don't you call Jack Wilson at Stewart? His number is (336) 859-2555. I found him to be very helpful..

Bill:
I agree, call stewart. Not all stewart's pumps are shown online ... stewart makes/made additional variations of shaft od & pump length. (example pn 32100 short stage 3 w/ 5/8" pilot)

Note: not only did chevy use 2 shaft sizes ... "short" pumps also came in 2-3 slightly different lengths ... with vette being longest "short" pump.

What's your prob? ... do ya have pulley with a big 3/4" hole & a pump w/ small 5/8" pilot shaft? ... or the other way around?

I'm running a weiand TG short race pump (not vette specific) ... had to shim the wp pulley out toward rad. I had a stock fan on my 71 sbc vette. My weiand has a 5/8" pilot ... so I used a small piece of copper plumbing connector to make a bushing to fit the 5/8" pump pilot & 3/4" hole in fan clutch ... real simple ... hardware store had box with 100's of em. Alotta new replacement fan clutches come with a bushing in box so one clutch can fit either pilot. Stilll, I dunno "why" the change in pilots?
JACK:gap

 

[billybob]

Thanks guys,

Actually I hadnt even tried to use it yet, other than measure it up against the original/old one.

All lines up nice with the exception of the shaft, even on a dry fit the pulley is interesting, and I may go your route Jack.

I was just mainly concerned about strength and what nots.

Thanks again


Bill