Short water pump for 5.7 vortec.

[Chilly178]

I want to put a short water pump on a new 5.7 vortec that i'm gonna put in my 72 C20. The parts guy at gm said any short water pump would work, but i'm skeptical with the plastic timing chain cover a lot of people had fitment issues that I see online about having to change out or shave some bolts. I just want somthing that will bolt on without issues and will work with my original v belt pulleys that I want to use. I found one water pump that claims it is designed to fit over the cover its the https://www.summitracing.com/parts/edl-8810/overview/. A little expensive but if its made to fit then it might be worth it. The parts guy at GM showed me this waterpump and told me it would fit. https://www.summitracing.com/parts/nal-19168604 I see they are different pilot diameters too, can someone explain what the piliot diameter is and what one i will need for using orignal v belt pullies from a 72 350 and a standard rotation water pump on a newer 5.7 vortec (l31-r)? One guy in the revews of the gm water pump said their are two different lengths of short water pumps and that one is the longer one? I'm not sure what one would be the right application or what the short one even is. The parts guy was also pretty sure that my orignal manifolds would not fit even though some members on the board said they will. Any input on that? Thanks

[Mike C]

The larger pilot is for the Corvette pulleys and fan clutch. Just buy a pump for the year vehicle you are using the pulleys and fan assembly from. If the motor is out, why not put all new gaskets in it while you can along with a stamped steel timing cover and not have to worry about it.

[jocko]

Pilot dia is the width of the nub that the pulley centers on. Vortec intake manifold is required to ensure a good seal - bolts are vertical, not canted like original. As for the timing cover - I’m with mike, replace with stock steel and call it a day.
Have never heard of two different lengths of short pumps, curious to hear where this goes.
I’m interested in the same conversion you’re doing, and am learning there are a few nuances of which to be aware. Also note that there is no mech fuel pump boss on a L31R, you’ll need an electric one. None of the little issues are insurmountable, many folks have already done this swap with no issues. Personally, I’m on the fence between the L31R and an HT383 ($ being the primary decider... ha)

[Chilly178]

Thanks for some insight. I was talking about the exhaust manifolds not the intake sorry should have clarified. I have all my stock pulleys/belt I want to use them with the new engine. I’m either gonna go with the Edelbrock or get one from Napa and buy a stamped cover. Anyone know if the Edelbrock 8810 is the same pilot diameter as the stock water pump for 72 c20 but it’s just made to fit over the plastic timing chain cover? I can measure the old water pump too when I get home. Thanks

[B. W.]

OE rams horns will fit the L31.

[B. W.]

Forgot to post pic! (These are 2.5 vette manifolds)

[weim55]

I've done the swap using a Vortech 5.7 from a 1999 suburban. I used long style water pump and Accessories drives on mine so I can't help you there. If someone makes a stamped steel timing cover for this application I'm unaware of it. The plastic timing cover on the Vortec is completely different and will not interchange with the old style stamped steel small block timing cover. The cylinder head uses a metric fitting where the temp sender would be installed. You will need an adapter for that to run a stock temp sender. I did not run stock exhaust manifolds but something to check while the engine is out: Bolt on the exhaust manifolds and check for clearance around the spark plugs. The spark plug placement is different and makes it very tight in spots. I had to modify my headers slightly for this. You'll be very happy with the upgrade of this engine, makes a tremendous difference over the stock 350.

Steve weim55 Colorado

[weim55]

Something else I noticed in BW s pictures, check for clearance for the passenger side dipstick, the flywheel pattern is different to at the crank, you will need to replace that too.

Steve weim55 Colorado

[dell72]

Originally Posted by weim55

If someone makes a stamped steel timing cover for this application I'm unaware of it. The plastic timing cover on the Vortec is completely different and will not interchange with the old style stamped steel small block timing cover. The cylinder head uses a metric fitting where the temp sender would be installed. You will need an adapter for that to run a stock temp sender.

Steve weim55 Colorado

I have converted several L31 350's to a carbureted application and to a steel timing cover. All that was needed is the alignment dowels installed in the block for the timing cover, as the holes are already there and two additional holes drilled for the old style timing cover. all else interchanges.

As far as the temp sending hole in the cylinder head, the hole is S.A.E. thread and a standard pipe plug or sending unit adapter will fit, although the diameter of the hole is smaller on the vortec heads compared to old style GM iron heads.

[Chilly178]

Or you can just run the sending unit in the intake like I plan to do.

[weim55]

Originally Posted by dell72

I have converted several L31 350's to a carbureted application and to a steel timing cover. All that was needed is the alignment dowels installed in the block for the timing cover, as the holes are already there and two additional holes drilled for the old style timing cover. all else interchanges.

As far as the temp sending hole in the cylinder head, the hole is S.A.E. thread and a standard pipe plug or sending unit adapter will fit, although the diameter of the hole is smaller on the vortec heads compared to old style GM iron heads.

I thought about doing exactly the same thing and drilling the missing holes in the block to accept the old-style timing cover, The problem I ran into is the stock link style timing chain hit the cover. The stamped steel cover did not have enough depth. Something to do with the roller cam?? Maybe stock steel stamped covers come in different depths?? Double up the gasket for clearance??

I really wanted to run the stock steel Cover and balancer so I would have a proper matched timing Mark and timing tab for use with a timing light in my carbureted HEI application. I degreed The Vortech balancer myself for use with the timing mark on the plastic timing cover. It's visible between the long water pump and the cover with a timing light. With a short water pump this mark is completely covered and unusable. To use the original stock steel cover and timing tab would really help as it's designed to be visible with your short style accessory drive set up.
Steve weim55 Colorado

[jocko]

Thanks for the clarification Chilly - sorry, yes, exh manifolds fit (good pics BW). Steve - helpful info, thank you from me also - was not aware the timing cover was not interchangeable.

[Chilly178]

Interesting.

[jocko]

Personally i prefer the sender in the head - member BrianMac has, at least in the past, turned down a few stock senders and re-threaded for me to fit the smaller opening, might be worth asking.

[jocko]

Well, I can't answer your question - but I would not think the Edelbrock pump pulley mount flange would be any different from stock or anyone who put it on an old block would have alignment issues. I would have to assume the extra timing cover clearance would have been carved out by slimming down the backside where it clears the cover without sacrificing final pulley centerline. That would be bad fer business...