# 1968 LeMans 350 water pump



## levilynch (Sep 28, 2020)

The car is a 68 LeMans that supposedly has a 350 but possibly a 400. When I first got the car I noticed that any time I revved it that there would be a high pitched whining sound coming from the front of it. After generously applying belt dressing I noticed that the problem still persisted and while at the front of the car when it was idling I could also faintly hear what sounded like metal on metal contact that sounded similar to the high pitched whining at higher rpms.

While the car was off I checked to see if the fan had any play in it that might indicate wearing of the water pump and ever so slightly I could wiggle it and the wheel it's attached to. It's been to cold to go out and pull apart to see if it's just because they're loose or if the play is coming from the input shaft.

While I wait I wanted to see about any recommendations for what water pumps are inexpensive but made well enough to not need replaced any time soon.

Also while I'm at it I might as well see about recommendations for a decent quality electric fan to replace the mechanical one with.


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## armyadarkness (Dec 7, 2020)

It matters if it's 8 or 11 (I think) bolts. They don't make an aluminum pump for the 8 bolt models... but if you want an aluminum pump and you have an 8 bolt model, then you can also get the timing cover, which accepts the newer pumps. However, if cost is a concern, you probably wont be going that route. Pontiacs tend to have cooling issues, so I personally wouldn't cut corners there. I just blew an entire Sunday, waiting for tow trucks, due to a "new" water pump from the "parts store".

So, yes I spent a lot of money to get the best upgrade, but going back, I couldve done that ahead of time and then not lost an entire day, stuck on the side of the road with GF, and $200 tow bill.


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## armyadarkness (Dec 7, 2020)

BTW, the day before, mine did what your did... Squeal. When it let loose, the power steering pump took out the oem fan. 67 GTO clutch fan made it 55 years, only to be killed off by a cheap water pump.

When replacing, I used a Flow Cooler pump, a high flow Mr Gasket thermostat, a replacement divider set, a flex fan, and a Cold Case Radiator. It was costly, but not as costly as the consequences and inconvenience, especially for a car that notoriously runs hot and is driven daily in the summer. Now it runs at 160 and the heat is awesome (fast).

Whatever you do, definitely buy two bottles of flush, and run them well, PRIOR to swapping out the pump. Then backflush it and only fill it with distilled water and af mix. No tap water.


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## O52 (Jan 27, 2019)

A big problem with parts store water pumps is their lack of quality control and non-factory impellers. Always, always insist on a factory cast iron impeller that is pressed on to the correct height. You will have to measure the height with your plates and adjust the sheetmetal if necessary.

Hold off converting your fan to electric until you've cleaned up your coolant system. It may not be necessary.

Or, send your pump to the Dutchman. 






** Flying Dutchman Remanufactured Rebuilt Water Pumps Import **


We rebuild and remanufacture water pumps for most import and domestic automobiles, including antiques and classic cars.



www.fdrbp.com





Impeller Adjustment






Clearancing 68 Water Pump Plates - PY Online Forums - Bringing the Pontiac Hobby Together


Clearancing 68 Water Pump Plates Heating & Cooling TECH



forums.maxperformanceinc.com


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## levilynch (Sep 28, 2020)

I appreciate the responses. I know it's difficult to see but I figured I'd post some pictures incase I'm missing something. Also to give you guys an idea of what I'm working with. In total I counted about 11-12 bolts. The reason why it's not a definitive figure is that one of the holes is empty and there's one in this recessed cavity underneath the alternator between two bolts that looks weird. Since it's about 11 does that indicate whether it's a 350 or a 400? 

What's another way I can find out what the motor is? Typically valve covers have a sticker indicating but this motor looks to be rebuilt with non original valve covers. I believe the VIN on the car said it came with a 350.

I wouldn't mind an aluminum pump to save on weight and to dissipate heat a little better. My main reason for wanting to opt for inexpensive is because I'm not really all that attached to the 350, but I definitely don't want to replace it due to cooling issues. A 400 however I would be more keen to invest into.



armyadarkness said:


> BTW, the day before, mine did what your did... Squeal. When it let loose, the power steering pump took out the oem fan. 67 GTO clutch fan made it 55 years, only to be killed off by a cheap water pump.


I've had a water pump give out on me on my 77 f150. Although that one didn't ever make a whining sound, it did puke all over the ground a few times from the relief valve on the pump itself until one day it just gave out completely and started flopping the fan all over the place. Figured I'd get the preemptive jump on this one.



O52 said:


> A big problem with parts store water pumps is their lack of quality control


That's been my experience for a majority of parts store parts for these older vehicles. I figured the best route would be aftermarket but it looks like there's a lot to choose from.



O52 said:


> Hold off converting your fan to electric until you've cleaned up your coolant system. It may not be necessary.


My main reason for wanting to do this is more to deal with the parasitic loss in power from the mechanical fan. I know it can range from 10-20 hp which can be better spent at the wheel. I haven't experienced an issue with cooling yet, but I also hadn't really saw a water temp gauge or any aftermarket gauges that can relay that info to me so I need to get on that as well.

Are the issues with Impeller clearance as severe with the better quality aftermarket water pumps?


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## O52 (Jan 27, 2019)

Power loss isn't that bad with a factory fan. You have a factory flex fan and the blades flatten out at high speed minimizing horsepower loss. Electric fans meanwhile are power hungry devices. The load they place on the alternator can be substantial. Plus you have to upgrade the charging system with a 100+ amp alternator, larger size wiring, temperature switches. Gets expensive fast. 

Your engine, or at least the timing cover, is 69 or later. 68 and prior engines had an 8 or 4 bolt pump. 
If you supply the numbers and codes shown below we can tell you what you have.
Block casting code is actually a number

The quality of over the counter pumps is hit or miss. Cardon rebuilds the majority of pumps sold OTC. Best bet is to buy new or send off to be repaired. Water pumps are the same for all engines of a specific time frame, doesn't matter if they're a 350, 400 or 455. The only oddball in late model V8 water pumps, is the early 69 with a short shaft.

And don't sell the 350 short. With the right cam and a 4 barrel QJ it will pump out over 350 HP. Thats stock GTO power.


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## levilynch (Sep 28, 2020)

That's true. I had neglected to think about all the other components that went into an electrical cooling system. Ideally I'd lessen or mitigate as many parasitic losses coming from the engine by adding roller components and other hardware. I've included some pics of the car just for show. 

being that I have the front of the car up on stands it was difficult getting in close enough to look for the codes. That and I believe that hideous paint is covering them. I'll have to wait for a warmer day to get a closer look. In the meantime I did include some pictures of the engine

Are there any aluminum pumps that you'd recommend or any reason not to get one?

With something like a 350, what would one roughly pay to get a cost effective amount of power out of it?


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## O52 (Jan 27, 2019)

The 350 HO with an 068 Cam, QJ, and 10.5 compression from 68-69 put out 320 HP. It wasn't a big seller and was dropped in 1970 when the 400 became available in the Lemans/Tempest. Became the standard engine in the 74 GTO but with around 7.9 compression and 180-200 HP. Not much love for the Pontiac 350 but some have actually pulled over 400 HP from them. 600 HP as a race engine
Here is a long thread regarding the 350. Limitations, stroker options etc. It costs about the same to build a 350 as a 400 but the prices for 400/455 blocks have steadily increased while you can get a 350 for dirt cheap. 






350 Block Stroker Builds ? - PY Online Forums - Bringing the Pontiac Hobby Together


350 Block Stroker Builds ? Pontiac - Street



forums.maxperformanceinc.com





But lets see what you have.


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## levilynch (Sep 28, 2020)

Thread is a bit of a read so I'll have to look into it as I have more time. Looks to be a lot of people crapping all over the 350 in favor of the 400 on the first page but honestly I'd prefer a 350 or a 400 over a 455. From my understanding the 455 is crippled due to the integrity of the block, correct me if I'm wrong?

I know that the right compression ratio and flow will make a massive amount of difference on any engine and I've even contemplated dropping my 351m/400 ford in it as it's been built and is waiting to be installed in my 77 f150 and just install a 460 in that, but that likely wont happen as it's far easier to just keep and modify the 350/400 that's in it.

It'll be about a week before I'm able to get out and really inspect what I have under the hood. Before I drop it from the jacks I gotta hang the mufflers since they're dragging and wait for the incoming weather to relax since I don't have a shop to work in. I appreciate everyone's responses to this point. I'll further post once weather and time permits. If you guys have anything else to add feel free to.


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## armyadarkness (Dec 7, 2020)

My 66 had a 350 in it and it was a maniac. Very easy to squeeze 350-375 horses out of one. As for the cooling system, just look at it as a whole. A great pump with a clean system, good plates, a high flow thermostat. Your pump is late model, so Stewart is the best (typically). Personally, I would keep the 350, but its parts will all fit on a 400, if that's in your future. 

I dropped at least 50 degress with my changes, and the previous owner could not get it to cool. Nothing ruins your day like an overheat.


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## Montreux (Mar 8, 2009)

The block casting number (top of the block, either near the distributor hole or behind the passenger head) will tell you the displacement and year of manufacture. See wallaceracing.com


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## levilynch (Sep 28, 2020)

Today was a nice day out so I managed to get some work done to the car however it seems I've discovered 20 more problems. The one thing I was able to get was the EUN and the engine ID. What do they tell you about the engine? the codes in the back are a major pain to get to as well as the serial number on the front of the block. I've also included some pictures of what the weather was like for the Pontiac. But, it seems I have far greater problems than the water pump. Once I managed to crawl underneath the car I saw the butchery the previous owner had put it through.

The crossmember was completely mangled and up against the u-joint as well as being torn from the transmission mount. Once I cut the mufflers off the crossmember just fell. the brake line to the rear end is dragging across the driveshaft and the left engine mount isn't connected to the engine. To make matters better, there is a horrible tapping sound the likes of which I have never heard coming from the rear of the engine. I'm thinking a severe lifter tap. I'm just hoping the cam isn't destroyed because that's how bad the sound is.

It will be a few months before I'm back on the water pump situation given my circumstances. I managed to remove the pully and spin it freely but I didn't hear it making any noise aside from it moving water. What would be your recommendations?


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## O52 (Jan 27, 2019)

Well a few things stand out to me,
1. It's cold there
2. Based on the EUN the engine is a late in the model year build.
3. WD could be anything from a 350, 389, 400 or a 455 HO. Need that date code near the distributor to tell exactly. Cylinder head code 6x means the heads aren't original to the engine or to the car.
4. If that 11 bolt water pump is original to the engine you probably have a 69/70 400, a 72 455 or a 73/74 350.

Time put that engine hoist I see in the background to work.


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## levilynch (Sep 28, 2020)

O52 said:


> Well a few things stand out to me,
> 1. It's cold there
> 2. Based on the EUN the engine is a late in the model year build.
> 3. WD could be anything from a 350, 389, 400 or a 455 HO. Need that date code near the distributor to tell exactly.
> ...


Thanks for the response. It was cold but it has since thawed and was a comfortable 70 out. I did a little more reading and found a displacement stamp on the left side of the engine towards the front. Looks like its a 350. If they were gonna change the engine they could've atleast swapped in a 400.

As far as the other issues involving the engine I should probably start a separate thread.


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## O52 (Jan 27, 2019)

It appears to be a 73/74 low compression 350 based on the info

Just type in the code wd into the search box (scroll down)



Wallace Racing's Pontiac Engine Search


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## levilynch (Sep 28, 2020)

Appreciate the info. Well atleast I can boost it, lol. Back to the main point. In the next few days I'll pull the water pump off and inspect the internals to ensure that it's not at risk of failing. Are there any lesser known signs to look for?


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## O52 (Jan 27, 2019)

Nothing really to see when you pull the water pump off and frankly speaking there are bigger problems as you have noted. Its easy for us to give information without knowing your budget or other constraints. Rather than pour money into an engine you are replacing anyway start looking for a good 400 core and deal with the chassis issues first. 

There's lots of good information here and we're all glad to steer you in the right direction. And please don't use the cinder blocks to hold up the car.


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## levilynch (Sep 28, 2020)

The car is up on jack stands. The blocks are just an added layer of protection. And to be fair, it's better to just spend the money to do something right the first time then to cheap out only to have to redo it later. I appreciate the help with the issues. I'll be starting a new post focused a specific issue at hand.


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## 1968gto421 (Mar 28, 2014)

O52 said:


> A big problem with parts store water pumps is their lack of quality control and non-factory impellers. Always, always insist on a factory cast iron impeller that is pressed on to the correct height. You will have to measure the height with your plates and adjust the sheetmetal if necessary.
> 
> Hold off converting your fan to electric until you've cleaned up your coolant system. It may not be necessary.
> 
> ...


I checked out the Flying Dutchman site. Sounds really good except on Pontiac water pumps they mention replacing the impeller. If I send them a pump to rebuild that has the cast iron impeller, will they replace it with one of those crappy stamped steel impellers?


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## levilynch (Sep 28, 2020)

1968gto421 said:


> I checked out the Flying Dutchman site. Sounds really good except on Pontiac water pumps they mention replacing the impeller. If I send them a pump to rebuild that has the cast iron impeller, will they replace it with one of those crappy stamped steel impellers?


Pretty sure if they have the capabilities to rebuild numerous water pumps to a condition better than original that they could probably build it to a customers specification and application as well as give recommendations for a desired outcome.


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