4.3 liter water pump question

I won't go into the long story, but I want to install a 1985 Chevy full size van 4.3 liter motor in my street rod. Every inch counts, so I want to install a short shaft (snout) water pump on the motor. I have run into conflicting information so I need some educated guesses here...... First, I do not plan on having any heater... those will be plugged on the water pump... second, I will mount the alternator in a different place... my problem.... What I need to know, is if I can order a short shaft water pump from anyone and will it work on this motor?Thanks


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Depends on what 262 V6 you have. The short pump will work on the 85-92 262 with the sbc type timing cover and should work with the metal timing cover on the 92-94 balance shaft engine. The 96 and up balance shaft engine with the plastic timing cover may give you problems with clearance. The plastic cover can not be replaced with the metal cover on the balance shaft engine has a different bolt pattern.
So should work for your engine.

Also plugging the heater hose can be done but it is recommended to drill a small relief hole in the thermostat plate to allow some flow through the stat when the thermostat is closed, to stop an air cavity from forming under the thermostat. An air cavity will interfere with proper thermostat operation. The heater flow helps with this when connected.

This is becoming a common mod on some v8 s-10 swaps when looking for more fan space. Since they are the same as the v8 pumps, you can install a corvette short water pump '88-9(?), which is shorter than the normal "short" water pump, along with a mercruiser flat pulley #807729T. This will put the belt contact surface of the pulley in the same place it was with the long wp and deep pulley. Note, the '88-up vettes were reverse-rotation pumps (serpentine belt).
If you have v-belts, I think you just need the pre-'88 vette v-belt pump, instead, as well as a similar flat v-belt pulley (don't know if there is a mercruiser pulley for this). Sometimes there is a little clearancing to do to accessory mounting brackets if you have the big cast aluminum serpentine belt brackets, since the lower hose will be a little closer to the front of the block.

Thanks guys for the advice.... I have also bent some other ears, Summit and Speedway, and sometimes I get too much information. For some reason, the water pump for a 1985-86 4.3s are not the same as 1987 up and I wondered if it was a major difference. Apparently, there is not and the differences would be for peripherals like the heater hoses etc. Both outfits offer a SBC short shaft and I have even bid on one in Ebay right now. I have some experience with air build up when I changed the water pump on a 1998 4.3 and found the relief plug on the top of the intake, I believe it was.... been awhile.... I will drill a hole in the thermostat as suggested though as I have heard that before. I will only have one pulley on the water pump for the alternator which will be located "somewhere else" and that will be determined AFTER the engine is installed to see where it makes the most sense. I have seen three different locations for that mount. One problem down, about 100 to go... thanks again.

'87-up are reverse rotation for use w/the serpentine set-up. If the BACK side of the belt turns the w/p, it's reverse rotation. If you are using a conventional V-belt pulley arrangement you want a standard rotation pump.

Hey...Cobalt327.. That is the exact answer I was looking for! Thanks.... I still am waiting for tech support to answer from Edelbrock, but have heard back from Speedway and Summit and got, at best, conflicting information.... thanks again.

Just got an email reply from JEGS, and they bailed on any suggestion. Guess I can't blame them. But I was thinking of the information I got, and put two and two together and wonder what everyone thinks.... The information I got said that SBC motors pre 1968 were for the most part, short shaft water pumps. Keeping in mind that a 4.3 is smaller version but pretty much the same, why not buy a water pump for a pre 1968 from an auto parts store? I went online to Advance Auto and pumped in a 1965 Chevy Impala with a 283 and then looked at the water pumps.... they all were right, short shaft, and one for less than $20.... Anybody got any ideas why that would not work on this motor? Just making sure I don't miss the obvious....

There were some differences in the fan bolt pattern and the shaft diameter (earlier pumps had a smaller shaft and small bolt pattern), but as long as the fan you use matches the W/P bolt pattern (many pumps will have a dual pattern), the shaft diameter is kind of a moot point- unless you're running a lot a accessories that would be driven using the W/P pulley. In that case the bigger shaft makes sense. But if this is a simple front accessory drive deal w/maybe a P/S pump and alternator, don't worry about the shaft diameter.

Not only will there not be a power steering pump, there will be no A/C, and the only "accessory" running off the water pump will be the alternator.... that's it... the fan? I might add that to the pump if there is room. However, I fully expect to have to mount an electric fan but don't want to. I think they are ugly especially on the outside of the radiator. There are a lot of ifs yet in this deal, but I cannot for the life of me come up with a reason why a 60's short shaft pump would not work if I am real careful about the pulley system to the alternator and I might need to ask some questions at that time.... thanks again everyone for the help and suggestions....

It will work as long as you use matching short W/P pulleys and brackets.

Good luck!

I have been down that road a bit already.... I bought this motor, instead of an older Chevy V6 because you can put the crossmember mounting system on the front of the 1985 4.3 V6 motor.... instead of conventional motor mounts that I don't have room for.... now, with that mounting system, you have eliminated a couple of options for an alternate location for the alternator bracket.... but there are others... I just won't know where it will literally fit the best.... at this point, I want the alternator to look decent, but more important is that it will be functional and safe..... It is a one step at a time process and when doing this kind of work, isn't it always? I try to plan ahead, but the bottom line is that money usually dictates what you wind up doing. I don't own a checkbook like a few of my friends..... LOL.... I did find a narrow seat for the truck (there was no interior and I love to do this work) from Craigs List, free, from a Mercury Villager middle row seat. I bid $21 delivered on a Moroso short shaft pump on Ebay but have one more bidder so far... I will probably lose that in three days and head to Advance Auto for a cheap water pump from a pre-1968 SBC motor..... Thanks again everyone....

So, I just lost the ebay bid on a Moroso water pump so I am going to visit my local parts store and try to buy a water pump for a pre-1968 SBC water pump, which will be a short shaft normal rotation water pump. I will install it on a 1985 Chevy 4.3 liter V6. Question: I am assuming the 1985 motor had a serpentine belt and would have been reverse rotation flow on the water pump (counter clockwise). The pre-1968 water pump will be normal rotation (clockwise). Considering nothing will be run off this pulley other than an alternator, does the direction of flow make any difference at all?

None whatsoever.

I don't have the alternator off this 1985 motor, and I have several old alternators on the shelf that I will have checked out to make sure it works before figuring out where to mount it, but I am just curious about this more than anything else. Suppose I did have the alternator for the 1985 4.3..... and I assume since it would be a serpentine belt and reverse rotation, that alternator would actually turn counter clockwise as well? Would there be polarity issues if you changed the pulley from serpentine to a regular belt and tried to run this alternator on an older, say, 1965 Impala? In other words, would there be something like polarity issues? I am NOT going to do this, but I am curious about anyone who has ideas about this..... Thanks

An alternator generates current the same in either direction. The only thing you might run into is the cooling fan of the alternator might be directional.