[455HOUK]

Past posts have suggested to drill 2 small holes in the block between the centre two cylinders to connect up the existing water holes in edelbrock heads to block water flow.
If you do this mod how thick is the block deck in this area?

[bad69bird]

Hopefully someone has done this. I've been curious myself and have heard of it being done...just haven't seen any pics and/or direction on how to do so.

[OINK 1]

Hi,
I do it all the time ! Drill away, the trick is bigger hole in gasket, I use a paper hole punch,
( don't tell wife, she'll kill me !).

The BIGGER deal is to take the H2O pump divider plate and bang around,( rubber mallet) the large center hole( intake). Smack it ( go all the way around it, eye ball it, it's easy, don't be chicken, you can always flip it smack the other side))and keep checking it on the pump, run the divider as close as you want, EVEN JUST TOUCHING !!. Cause when you add the gasket, now there's .015" clearence. After you've bolted on the pump, give it a spin to make sure it ain't touching.
Sucks to do after the sealants have set up.
water pump bolts w/ anti sieze- 15 ft.lbs
Timing cover 30ft.lbs., oil on bolts,heads,in block( like use a Q-tip).

Run the C.A.T. ( yes CAT) 11 bolt H2O pump, top notch unit.
Spiral impeller, big bearings and seal.
I sell them if you want 1.

Look on web:

http://www.pontiacengines.net

Pontiac Gregg
1-303-776-0877

[johnta1]

Steve B. has done this.
I don't think it's any thicker than where the other water holes on the deck are.

[Steve Barcak]

I've lived in one of the hottest parts of the country most all of my life. For some time, I had the normal hot running engines and related issues that most still have. I did considerable experimenting in the late 80s and early 90s on Pontiac cooling systems to get them to run cooler.
As far as I know, no one has more miles on Pontiac engines than I do. I am talking about first hand- building my own, driving my own, tearing down my own...well over 500,000 miles on Pontiac engines- street, strip, marine, including lots and lots of heavy towing. My engines have no cooling issues even with A/C and pulling a trailer in 115 degree heat.
Adding a hole in the deck has been something I have done now for 15-20 years with several hundred thousand miles doing it. Furthermore, I also tap and plug other holes in the deck.
these mods are simple, inexpensive ( under $10 ) and really help to put the water where it needs to go. Too many Pontiac motors run cool on the front cylinders and hot in the back and in the very middle.
Not knocking water pump mods...maybe they work, maybe they do not. I do not know from experience because I had never had a need to make further improvements. My systems run so cool, I have to change thermostats in the winter so my Pontiac engines will have better heater output. When I drive in the snow, I usually have to go further and block off part of the radiator with cardboard for better heater output.
I will not build a motor without these mods.Here ore some pics I took of a block for you.
It is dirty but, you can see what i change. I have marked the areas with a black felt pen.
I plug the 3 holes on each side with a 1/8" pipe allen plug. the blocks tap easy. try not to tap too deep as pipe thread is tapered. Tap a little at a time and test fit the plug until it sits just below the deck. If you go too deep, you can use thread lock, otherwise it is not needed I prefer to use steel plugs but, you can use brass.
On drilling the center holes, use the gasket for a template and center or transfer punch. Use a new or very good condition, high quality bit. Be extra careful, when you get to the bottom of the decks thinkness, the bit tends to want to catch and can sometimes snap. Use the largest bit you can instead of normally using a small to start. this is because you need the strength of the bit. Do it slow and use oil.
here are some pics.
Hope this is helpful to you, this works for me like a charm. I have never had a need to use external lines and pump mods like others use.

You may ask WHY the gasket has the hole and the block/head does not. Well, the early Pontiac blocks ( that I am so fond of ) actually HAVE this cooling hole! ) for some reason, Pontiac engineering decided the eiminate this hole. This was another mistake they made and I could not tell you why.
Steve


Hosting 11th annual Pontiac Heaven, show, swap, drags, party and all around good time. Saturday April 4, 2009 at Speedworld near Phoenix, Az
Also hosting- 7th annual Nostalgic Show and Go! and swap coming Sunday April 5, 2009 to Speedworld. Phoenix, Az

[OINK 1]

hook the rear H2O passages togther and T them. Go to heater core or back to intake x-over.

Pontiac Gregg
"Keepin' Kool"

[Steve Barcak]

"hook the rear H2O passages togther and T them. Go to heater core or back to intake x-over." I see lots of guys doing that.

Well, maybe that works and maybe not. I do not know. My from 100s of thousands of miles experience with my Pontiacs in the Arizona desert, I have not found it necessary.

Steve

Hosting 11th annual Pontiac Heaven, show, swap, drags, party and all around good time. Saturday April 4, 2009 at Speedworld near Phoenix, Az
Also hosting- 7th annual Nostalgic Show and Go! and swap coming Sunday April 5, 2009 to Speedworld. Phoenix, Az

[cgeise]

Can i ask -- have you run this set up on any really high c.r. engines - and was there ant issues with water getting in the cylinders

[Region Warrior]

Do you mean adding the "421" cooling holes?
Just use a head gasket as a template.

[Region Warrior]

Originally Posted by OINK 1

hook the rear H2O passages togther and T them. Go to heater core or back to intake x-over.

Pontiac Gregg
"Keepin' Kool"

Heater core...whats that?


If you want'm even cooler, bypass the heater core and timing cover.
Run'm directly to the x-over.

[BILL BOWMAN1]

I once reluctantly paid for this service. It was, in my opinion a 100% waste in every sence of the word.

[bad69bird]

Originally Posted by cgeise

Can i ask -- have you run this set up on any really high c.r. engines - and was there ant issues with water getting in the cylinders

Good point! With boost pressures and head gasket issues already that would be just one more thing to potentially worry about.

X2...Anyone with high C.R. have this done?

[DINO1]

12 to 1 compression, and no issues to date. KRE "D" port heads with Fel Pro gaskets. You do have to watch how big a hole you drill, the head bolt boss is right next to the location you drill the hole. I'm thinking I drilled an 11/32 hole and champfered it on the block side and the head as well. Good for a 40* drop in head temp on the center of the head, actually it helps to prevent blown head gaskets between the center cylinders.

[bad69bird]

Originally Posted by DINO1

Good for a 40* drop in head temp on the center of the head, actually it helps to prevent blown head gaskets between the center cylinders.

THAT'S WHAT I'M TALKIN' BOUT!!!

[Tom Vaught]

The "421" Mod seens to work for a lot of people.

The Mods Steve has shown seems to work for a LOT of road vehicles.

The problem, in my mind, is not at all with the Dry Deck block on a blower engine. If you want more cooling between the exhaust ports, drill on the heads not the block. Get a E-Head core from someone
who has cut one up in the past, look at the water jacket in the exhaust side between the center ports and then add an external water feed from the pump to that location. Chebby has been doing that deal for years.

Tom Vaught

[Tom Vaught]

Kurt Unban Quote:

"Urban says it's been difficult to keep head gaskets in it under the extreme boost generated by the twin turbos. "We've talked about welding up the water passages and running external cooling lines to the heads, which would at least keep the pressure out of the cooling system," Urban says, noting that some cylinder leakage out of the head gaskets is probably unavoidable due to the limits of the Gen III's 10 head bolts. "

The man has raced a few fast cars I believe.

Tom V.

[grnmnstr]

Originally Posted by Tom Vaught

If you want more cooling between the exhaust ports, drill on the heads not the block. Get a E-Head core from someone
who has cut one up in the past, look at the water jacket in the exhaust side between the center ports and then add an external water feed from the pump to that location. Chebby has been doing that deal for years. Tom Vaught

Tom,

Can you go into a little more detail on this mod? I am thinking of doing something like this. Is there a way to get to the water jacket on the Intake side of the head, between cylinders 4 & 6 and 3 & 5?

[lust4speed]

It would be very interesting to know why Pontiac eliminated the center holes in the block since this area is the most heat prone of any part in the head. Adding additional holes for cooling in the center of the head seems like a good idea. I would still like passages at the front for that exhaust valve, but would agree that they could be smaller since the coolant in this area has just been returned from the radiator and hasn't picked up much heat yet compared to the center and rear of the engine.

As far as the bypass hoses from rear of block to the crossover, doesn't the normal path of coolant exiting only at the front of the head provide for more heat absorption in the head? I wonder if the heads don't really run hotter with the additional plumbing. Water temperature in the crossover would be the same either way, but the center of the head might be hotter with this fix. The stock path forces all coolant to travel through the heads and out the front.

[taff2]

I drilled the 421 style cooling holes on my previous 12-1 406,and current 13-1 406, race use only ,never had any gasket problems in that area.

[440GP69]

Where exactly on a E-head would this line fitting need to be Tom V? I will be pushing mine a wee bit so I need to not have some cylinders way hotter than others Or Failier could follow!