converting a SBC long water pump to a short one..

what gives?? i've got to convert a long pump to a short pump. do all short pumps have the same deminsions? meaning, is the pulley higher or lower on some pumps?? the center to center length (from the water pump to the crank pulley) on the long pump measured 7", on the short pump it measured 6 1/2".... so i'm having trouble finding matching pulleys.

 

buy a short pump at the parts house. return long pump as a core. done

 

the pully wont be higher or lower.., on a short pump it is just like it says, Shorter, then the long one..so it doesnt stick out as far ..not as close to the radiaitor..pully face closer to the block..ie...shorter..I want to say like 3/4"

pullies will be different from the short pump vs the long pump

 

not only the pullies are different but all your alt,and other brackets will be different. so changing over from long to short isn't cheap i just did it so i know,unless you have a donor car.
hope that helps

 

Make sure the end is pressed on all the way. All pullies have to be replaced,including the crank pully. The cheapest way to go is a surpentine
from a 305 or a v6 chevy and run a elect fan.

 

The pump length is 1 3/8 " longer on the long pump. 7 1/4 inches compared to 5 7/8. Also there are a few different configureations for radiator hose location and heater hose location, as well as two different center shaft diameters, the larger shaft is for corvettes I believe. And oh yeah, don't forget about all new mounting brackets for alt/generater, A/C, PS pump, etc. etc. The first thing is to take your old long pump to the parts house and match up the hose connections and shaft diameter, then you can play with all the new brackets. Oh and one other thing, you will more than likely need new belts because of the different bracket locations. Just going to the parts house and changing your long pump for a short pump is not the end of the story. I just went through this on mine to gain some radiator clearance. I believe the short pumps were all pre- 1973 or so. Hope this helps.

Sorry for the redundant info but by the time I got this typed the other two chimmed in with the same info.

 

just get a short pump,got mine from speedway 40 bucks, and get short pullys from an older motor and alt bracket. im currently tracking down the pullys brakets myself

 

There is a long pump, a short pump, and a Corvette short pump, that is all, as far as I know, in terms of overall dimensions.

Pumps, all pulleys, and accessory brackets must match, at leas for pump type. If you can hit the local self-service yard, find something '68 or earlier in a car, or a little newer in a truck (I forget), and raid that for the parts.

One point of note, I have seen some variation in water pumps in the early '70's in trucks and vans, depending on whether or not they had power steering. Some, and it was just a few, did not have the lug on the pump to mount the power steering pump bracket. It was just smooth where it would be.

I am the only one who seems to find these long-shots, so you'll probably be OK.

 

oldschool66;6369522]The pump length is 1 3/8 " longer on the long pump

ahh ok..I was way off..I have nothing that runs a long pump so I wasnt sure on the length difference

 

i was told they are pre 68.

 

I believe that's right for pass cars but I'm pretty sure some trucks used the shorty up to 1973, but the rule of 68 or older is the one to follow.

 

i've already got the short pump, thanks to another HAMB'r.. he sent it with the pulley and fan already attached, he also sent a crank pulley with it (not absolutely sure it's the right pulley) when i bolt on the pump the two pulleys over lap by about 1/4"... so does pulleys come in different diameters?? the pulley that came off the long pump measured approx. 6 1/4", the pulley on the short pump measured approx. 7 1/8", both crank pulleys measured 7"

 

I used a generator bracket that was a driver side header mount and flipped it and mounted it on the two front intake bolts on the pass side. The tension bracket was a little bit of a project but I used an alt. tension bracket and mounted it off the front head bolt holes, that's why I love working on these things, makes ya think!!!

 

Go to the Bone Yard, or a U Pull Junk yard. Find a old SBC with a short water pump, and take it all. Or just the pieces you need!

 

There are several crank pulley diameters. I could guess at a number, but then, the next time I hit the yard, I'd find another size. The crank and water pump pulleys can be close together, but should not overlap, unless it is a stepped pulley, and it is the next groove over that is overlapping.

Belt groove alignment is what really counts.

 

Match the pullys. the crank pully fits about flush with the dampner while the pump pullys offset are different for short and long pumps. Measure the distance between the pump shaft center and the crank center, subtract 1/4 inch and that's the max diameter for each pully. I like to keep the diameters the same so you don't under or overdrive the pump.

 

does anyone know if the late alternator will work on say early short pump brackets?

i have an alt from an 80, and in going to shortpump just as the other fellow. i just done now if the alt will work or if they have different mounting holes..

 

Mounting holes are the same.

 

cool, i thougth they were, just wasnt sure, do you fellas know if the 65 style mounted off the driver side header? and if so that wouldnt fit behind a A shell would it?

 

think i'll head over to the bone yard and see what i can find....

 

Nope. Sticks out like a sore thumb. That's why I mounted mine the way I did. Used the header mount but tucks it up nice and tight to the pass side intake, and I'm running Tri-Power so it's really tight but it fit.

 

ah DAMN! well thanks for that. at least i know not to get that mount now,so i guess it would stick way to far out from the radiator.

how did you get teh alt nice and straight when you made a new bracket? im interested in this

 

Well, I used a header mount, which the hole spacing on the header flange and the intake manifold are the same so if you flip the mounting bracket over and up to the intake it lines up perfect. Then all you have to do is mount the tension adjustment bracket, I had a chrome one from a different project, it kinda has a 1/4 moon shape with a slot at the top and 2 holes at the bottom about 14 inches long, they sell them at O Riellys, I spaced it away from the head with a steel bushing and just make sure the arc of the alt. matches the arc of the slot in the tension bracket. I'll try to get some pics of the whole set-up and post em to this thread or e-mail em to you

 

that sounds cool, so you didnt use the 65 style mount at all? i havnt seen them so i dont know what to expect. what im asking i guess is i should pass on the mount and run something else?

i have the stock 1980 mount that mounted the alt were you mounted yours passenger side,but its for long pump. maybe i can chop it down to work.

 

Short Water Pump 355 Chevy.

 

I have use these with success, on Model A's, tucks it in real tight (bonus points: Alliance vendor, good people):

https://www.welderseries.com/blog/online-store/alternator-mount-kits/

 

oh man, thanks! even shows what the bracket does. awesome. thanks a bunch bimpy.

 

well.... no luck at the pick an pull. gonna have to come up with a plan "B"

 

If your heads have accessory holes then you can use mounts that were on Corvettes and trucks that bolt to the end if the drivers side head.

 

The Swap Meet next week!!!!!