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‘65 GTO, 400ci, tri-power, 4spd,
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Discussion Starter #1
Hey all, so I removed my heater core a while back cause it was a leaky mess and decided not to replace it, as I don’t drive the car in the Canadian winter or rain. Since then, I’ve been running the heater hose from the water pump directly to the port on the back of the engine, but I’m wondering if I can remove that completely and just cap off both ports. I’m assuming not, as it needs this connected in order to circulate coolant, but can I get a confirmation on that?
 

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I used the block off plugs on my 65 with no problems. Farthest it was driven at one time was about 40 miles. Many short trips and a few 1/4 mile trips. Be sure and check the plugs every year as they are easy to crack and leak.
 

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‘65 GTO, 400ci, tri-power, 4spd,
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Discussion Starter #4 (Edited)
I used the block off plugs on my 65 with no problems. Farthest it was driven at one time was about 40 miles. Many short trips and a few 1/4 mile trips. Be sure and check the plugs every year as they are easy to crack and leak.
Very cool (pun intended), thx guys!

What are you using to block these off? Can you post a photo, or link to anything available off the shelf?

cheers
JL
 

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The block off plates are available from several vendors, you will also need to find or make a dash plate.

138358

138359

138360
 

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Discussion Starter #6
Thanks!

what do you use to cap off the ports on the engine and water pump?
 

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‘65 GTO, 400ci, tri-power, 4spd,
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Discussion Starter #7 (Edited)
Found this online which could work nicely...I guess im just not quite sure how they’re supposed to attach to the water necks?

 

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Found this online which could work nicely...I guess im just not quite sure how they’re supposed to attach to the water necks?


Hmmm. Those look like replacements for your intake manifold water neck. I don't think you want to block off the engine coolant going into the radiator?

Measure the ID of the water pump water-to-heater hose outlet and the water outlet nipple on the back of the head. Then go to your local auto store and ask for a rubber expansion freeze plug. Enclosed a photo of what you are after. It slips into the pipe end and you simply tighten it down snug - not over tight. Never had one pop out in my experience, but not a bad idea to have a spare or hose/clamps the length needed if you should get stuck out on the road - not knowing how far you go with the car.

Rubber Expansion Freeze Plug.jpg
 

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Discussion Starter #10
Hmmm. Those look like replacements for your intake manifold water neck. I don't think you want to block off the engine coolant going into the radiator?

Measure the ID of the water pump water-to-heater hose outlet and the water outlet nipple on the back of the head. Then go to your local auto store and ask for a rubber expansion freeze plug. Enclosed a photo of what you are after. It slips into the pipe end and you simply tighten it down snug - not over tight. Never had one pop out in my experience, but not a bad idea to have a spare or hose/clamps the length needed if you should get stuck out on the road - not knowing how far you go with the car.

View attachment 138379
Hah! Right you are re that block off plate. My bad. Wouldn’t wanna do that.

That plug you mention above looks perfect. Didn’t know they made such a thing. You guys are making my day, appreciate all the helpful advice.

Cheers,
 

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Very cool (pun intended), thx guys!

What are you using to block these off? Can you post a photo, or link to anything available off the shelf?

cheers
JL
I don't have any pics, but I used the type that slipped over the top and attached with clamps. The brand I used was Dorman; off the 'Help' display at most auto parts stores.
 

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Never saw any block off caps that didn't rot away in a very short time. One of my friends had a cap rot off before he was able to finish the car and take his first ride. Best to use a 3" or so length of heater hose with the appropriate plug stuck in the hose. Looks strange but a sparkplug fits perfect in the 3/4" hose. Run a fake sparkplug wire to it and confuse the hell out of onlookers. At least the hose will go for many years before needing replacement.
 

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Discussion Starter #13
Never saw any block off caps that didn't rot away in a very short time. One of my friends had a cap rot off before he was able to finish the car and take his first ride. Best to use a 3" or so length of heater hose with the appropriate plug stuck in the hose. Looks strange but a sparkplug fits perfect in the 3/4" hose. Run a fake sparkplug wire to it and confuse the hell out of onlookers. At least the hose will go for many years before needing replacement.
good tip. I like the plug wire idea ;)

I looked for some expansion plugs as mentioned by Jim, but can’t find anything small enough. I need a 5/8” for the water pump outlet, and 1/2” for the one on the head, and they just don’t seem to make them that small. Found some rubber caps that fit, but like you said, worried about them rotting or blowing off. Maybe a rubber plug inside first, then cap and hose clamp could work?
 

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Never saw any block off caps that didn't rot away in a very short time. One of my friends had a cap rot off before he was able to finish the car and take his first ride. Best to use a 3" or so length of heater hose with the appropriate plug stuck in the hose. Looks strange but a sparkplug fits perfect in the 3/4" hose. Run a fake sparkplug wire to it and confuse the hell out of onlookers. At least the hose will go for many years before needing replacement.
My block off caps were very thick, and I never hade a problem with them. However, on the racecar I used screwed in plugs.
 
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