Is this the right water pump for an L31 Vortec with Vintage AC?

[geezer#99]

Water neck riser does no good. You already have a spot for your heater hose.
You need a spot to hook up a return line to.
Either on the water pump or on the rad. Your down flow rad doesn’t help with that. Return should be on outlet of rad which is the bottom tank on yours. I’m not sure if you’d get adequate flow down to the bottom.

[tdangle]

Just go to your local auto parts store and get a long pump for a SBC. I believe they started using long pumps in the early 70's on all chevy small blocks. My 70 has a short pump but has the heater return fitting and also I used the top fitting for the coolant bypass. Yes all vortec heads need some sort of bypass.

[msg]

I spoke with Edelbrock and what the tech said was that if the block has the bypass port/hole on the passenger side directly under the mount hole for the pump (which mine does), and if the pump has a hole on the same spot then that is all the bypass thats needed on a small block thats running old school v style pulleys. I need to just double check if that hole in the water pump mount continues through the pump to allow for the flow.

This is the pump I put on and remember the hole but didnt check if it went completely through and didnt dead end somewhere.

https://shop.advanceautoparts.com/p/...m=water%20pump

So if it all checks out then he said just run the heater return line to the top of the pump and cap the port on the manifold.

[Captainfab]

The issue is that even if your block has the bypass hole and the water pump does too, the Vortec heads do not have the corresponding hole drilled in them. All GM trucks with a small block or big block, 1972 and earlier originally came with short water pumps. There are atleast 3 variations of the long water pump used 1973-1987. Then in 1988 or so when the serpentine accessory drive was introduced, then you had a reverse rotation long water pump. Then the '96-'02 L30/L31 Vortec engines had yet another variation of the long water pump.

[msg]

Originally Posted by Captainfab

There are at least 3 variations of the long water pump used 1973-1987. Then in 1988 or so when the serpentine accessory drive was introduced, then you had a reverse rotation long water pump. Then the '96-'02 L30/L31 Vortec engines had yet another variation of the long water pump.

Would the water pump rotation matter for the engine I bought?

https://www.summitracing.com/parts/NAL-12681432

If not then should I just start searching Rockauto for c10 to c1500 trucks from 1973 to 2002 and see if I can find a long style pump with 2 ports in it, not unlike the one I started this thread question with? I wasnt sure if the long style press on fitting stems in that one could be removed and hopefully get some NPT barb fittings to replace it. Maybe Rocknrod was saying that the fittings are pressed into the pup and have no threading?

https://shop.advanceautoparts.com/p/...711/11936594-P

[msg]

Another thought from both Edelbrock and Vintage Air was to drill holes in the thermostat to solve the air pocket/overheating issue rather than going through all this. Bad idea?