True short water pump clearance savings.

[T97]

Before we start the engine is an l31 vortec that i plan on running a v belt system with only an alternator and mechanical water pump. Edelbrock performer(vortec) intake with a street avenger carb.

The reason i ask is im swaping this crate engine into an '86 d-50 so clearances are going to be an issue. I plan on cutting the radiator support and pulling the radiator and slim electric fan up against the grill and under the core support.

I see online that a long water pump is 7 1/4 and the short water pump is 5 5/8 long. My question is it truly a 1 5/8 savings in front of the engine? Does the short water pump pulley take up any extra depth that a long water pump pulley?

Im looking for the combo that gives me the most amount of clearance between the engine and fan. But if the difference isnt truly that much I would consider swaping to the long water pump and trying to make up the difference in another way since the long water pump brackets are so much easier to find.

Also i understand that the l31 originally came with reverse rotation water pumps since it came with a serpintine drive system. Will i run into any problems running the older style pump on this block if i make sure to get a radiator with the correct inlet and outlet?

Thanks in advance
T97

[kwmech]

The short water pump is indeed shorter in the long run. Will just need the pump pulleys and brackets. Nothing special being l31---still a small block

[Captainfab]

If your L31 still has the plastic timing cover, check for clearance between the short water pump and the cover before you tighten the pump down. GM says that you can not put a short water pump on a L31 with the plastic timing cover, but I have before.

[T97]

Thanks guys i appreciate your info. I planed on switching to the stamped cover anyway its just more aesthetically pleasing to me. Just wanted to make sure that the block didnt need reverse flow for some reason.

[kwmech]

Originally Posted by T97

. Just wanted to make sure that the block didnt need reverse flow for some reason.

Flow in the block is the same, water pump just turns backwards. Vanes in the pump are reversed

[Captainfab]

The only reverse cooling small blocks are the LT1 and LT4. Every other small block is the same. The only reason for a reverse rotation water pump is with a serpentine accessory drive. And then the coolant flows the same.