What are these and what for?
 

One on front of each head. I'm pointing at one. Might win ignorant question of the day.

https://scontent-sjc2-1.xx.fbcdn.net...61&oe=5883D030

Re: What are these and what for?
 

Looks like a water port. What engine is it, my guess a V6?

Re: What are these and what for?
 

402. The heads came off a 396. Actually more better heads. 402 had smaller ports I hear, 8.5/1 Vs 10/1 compression if I remember right. Come to think of it, that MIGHT be the difference where there are 400 badges with 396 blocks.

Re: What are these and what for?
 

I don't see many Big Blocks these days so not real sure on what they look like. I still think its a water port, also could be used for a Marine Motor. It was put there for a reason some one else might know the answer, mine would only be a guess.

Re: What are these and what for?
 

Possibly ignorant question two days straight.

Re: What are these and what for?
 

I assumed it was related to casting and not operation, but I honestly don't know. I broke a breaker bar trying to get one out once, so they don't yield easily...

Re: What are these and what for?
 

cyl hd coolant drain pipe plug. comes in handy when removing a cyl head so you don't dump coolant into the cylinder upon removal when the mating surfaces separate.

Re: What are these and what for?
 

Not ignorant at all, if you have the need to know then you ask a question and hope that someone comes up with the Correct answer. Have you tried chasing down the Casting Numbers and the Suffix code as well as the Heads Casting numbers this might just get you started in the right direction.

Show yourself your not a ignorant person by putting One Foot in Front of the Other. Life is a Journey so get to step'en.

Re: What are these and what for?
 

Very cool. Nice to have a name and function for things. Thank you, and all other replies.

Re: What are these and what for?
 

You bet Tony. And there are no bad questions. We all kinda operate under the assumption that we've all come to this site at different times in our own learning curves. I sure wish this site was around when I was 16. Well, actually, would've been nice to even have a computer around too.. but, I'm dating myself. Some guys start this stuff at 65 and are starting from scratch because they've worked their whole lives to be able to retire and START tinkering and some guys are tinkering at 14 yrs old. I've learned a lot here. Imagine how boring it would be if we all knew everything here.

Re: What are these and what for?
 

This website is awesome Jocko. So much info. and helpful. A lot of very cool dudes. I'm that 2nd guy described. I started this over a year ago, and I retire in December (55 yrs old). It's worked out so well. I've wanted to restore this for 25 years, and lucky as heck I've waited so long. Not just because I'm retiring, but what I did say 15 years ago may not be up to par now.

It's mostly all new to me. I've never even done a brake job, and here I am tearing her down. Wasn't exactly raised around tools (father protestant musician, mother "Jewish princess")............but I've made them a habit for the second half of life +. Now if I can just figure out this wiring. Man, these schematics are hard to read. Looks like I'm at the Relay Assm. and Relay Assm. Delay on the front firewall.

Re: What are these and what for?
 

Only an arrogant personality thinks a question can be "stupid" (or as it's been put here, "ignorant.")

Re: What are these and what for?
 

While I don't doubt they -can- be used as a drain plug, I do have some doubts about that being their reason for existing. I'd still like to know the rationale for GM including them in early castings, and why they went away eventually...

Re: What are these and what for?
 

I believe its just a galley plug.Removed when the head is rebuilt and machined to clean out the passages.

Re: What are these and what for?
 

My understanding is that they are used to remove the casting sand during the manufacturing processes. They were to hook up hoses to and flush the sand out of the water passages

Re: What are these and what for?
 

Pretty sure they call them "Pipe Plugs." They are NPT and can be used as an alternative for a temp coolant temp sensor. As far as also being used to remove casting sand, I guess they could be but not sure. I have heard you need serious heat, hardened tools, and a lot of muscle/leverage to get one out. Never tried myself.

Re: What are these and what for?
 

This

Re: What are these and what for?
 

I still think they were a foundry thing, not an automotive thing. Maybe they got better shaker tables to get the sand out and found they didn't need to use them anymore? Really wish I knew though.

Re: What are these and what for?
 

My 1969 CST 396 with an October 68 block date has them as well.....I was wondering also but didn't ask.....