Restarting My '70 Nova Project

[Fuddyduddy1952]

Years ago I pressure tested a block with a section of exhaust pipe I brazed a tire valve in middle. Pipe was sized so it fit radiator hoses.
So hoses clamped on motor and pipe. Then I could put about 20 psi air in it.

 

[dodge man]

Are you sure it’s leaking at the head gasket? If yes I’d put a new head gasket in.

 

[BravoXray]

Are you sure it’s leaking at the head gasket? If yes I’d put a new head gasket in.

Yes, It was definitely leaking from the head.

After finding the head bolts not being up to specified torque, I was mulling over whether just to retorque them and put it back together, or pull the head and take a look at the head gasket. I was wanting to get it back together and be done with it, but my spidey sense (Spider Man ESP) told me, "Dude, pull the head, there's something going on you need to see."
So, this afternoon I pulled the intake and then pulled the head, and I'm glad I did. There was no sign of leakage on the intake gaskets. At first glance nothing looked amiss with the head gasket, until I examines the area around the water passages at the lower rear and front of the head, and the impression they made on the head gasket. The passage in the head does not line up with the hole in the gasket or the block, and overlaps the line of sealant around the periphery of the gasket, as you can see in the pictures. In fact, the hole at the front of the head looks to be even a little farther off that the rear one is. Also, some of the gasket material stuck fast to the block at the very rear edge of it, the only place it did so. I verified that the head gasket is the one recommended in the instructions for the heads. The heads are a set of Procomp 3002's (Chinese knockoffs) that I got from a local shop probably 15 years ago, and obviously they were worth what I paid for them.
I don't think a different gasket would be any different, since the holes in the block line up with the ones in the gasket, and I not going to try to use some kind of sealant to put a Band-Aid on it.
So I think I'm going to check into another set of heads, and see what I can come up with and go from there. I might go with a set of AFR heads, or maybe Edelbrocks, as they have good reputations.
Engine Masters did a show a while back comparing different aluminum small block heads, and the AFR 195cc Enforcer was a great performing head at a decent price, so I may go with a set of those.

It's only money.....

 

[Alan46]

Bummer bro! You did good!
I used a set of AFR 202 heads years ago on my 13 to 1 427sb ford, perfect out of the box!Good luck with whatever set you get!

 

[dodge man]

Good find. I suppose you could attack the heads with a dremel and make things line up better but I could see problems doing that.

 

[BravoXray]

Good find. I suppose you could attack the heads with a dremel and make things line up better but I could see problems doing that.

To do it correctly, you would have to make and press plugs into the holes, machine them flat, then drill holes in the correct locations. That would probably cost more than the heads are worth.

 

[BravoXray]

I talked to a tech at Summit racing this morning, and made sure the AFR heads have the steam holes that are required when used on a 400 SBC block, and they do. So I ordered a pair, all the gaskets I'll need, and a new set of plugs, since AFR recommends a different plug than what I have.
This afternoon, I removed the other head and cleaned up all the parts, so once I get the new heads and get them checked out, I can start putting it back together. I have a big commercial parts washer, and it's great for jobs like this, but I always end up covered in solvent, so I ended up taking a second shower to get the smell off me. The pants and shirt are on the porch airing out until I wash them.
I used a new carbide gasket scraper tool for the first time when I was cleaning the block deck, and it works great. The instructions cautioned about using it on aluminum parts as it will easily remove metal and can damage a sealing surface if not careful.
I also pulled all the lifters one at a time and looked at the bottom of them and the cam lobes, and they all look fine, so it appears to have broken in properly.

It's supped to be in the mid 90s here tomorrow with high humidity, so I may work on a couple projects in the basement tomorrow.

 

[BleedingOrange]

What are you going to do with the old heads ? Will they match up with any type of block, or were they some kind of one of a kind ?

 

[Alan46]

I talked to a tech at Summit racing this morning, and made sure the AFR heads have the steam holes that are required when used on a 400 SBC block, and they do. So I ordered a pair, all the gaskets I'll need, and a new set of plugs, since AFR recommends a different plug than what I have.
This afternoon, I removed the other head and cleaned up all the parts, so once I get the new heads and get them checked out, I can start putting it back together. I have a big commercial parts washer, and it's great for jobs like this, but I always end up covered in solvent, so I ended up taking a second shower to get the smell off me. The pants and shirt are on the porch airing out until I wash them.
I used a new carbide gasket scraper tool for the first time when I was cleaning the block deck, and it works great. The instructions cautioned about using it on aluminum parts as it will easily remove metal and can damage a sealing surface if not careful.
I also pulled all the lifters one at a time and looked at the bottom of them and the cam lobes, and they all look fine, so it appears to have broken in properly.

It's supped to be in the mid 90s here tomorrow with high humidity, so I may work on a couple projects in the basement tomorrow.

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Good call on the heads!

 

[BravoXray]

What are you going to do with the old heads ? Will they match up with any type of block, or were they some kind of one of a kind ?

I'm not sure right now. I'm going to clean them up, bag them and put them on a shelf, then I may list them for sale on Craig's List or Marketplace. Without another block on hand, I'm not sure how the water passages will line up with those on other blocks, but I do know that head gaskets for most all SBCs are the same, except for those for a 400 block that has six additional small holes called steam hols, in the areas where the bores are siamesed. In addition, since the passages in question are offset about half their diameter from the holes in the block, that would cause a restriction in coolant flow.
That restriction could explain why the water temp on the Atomic EFI, that has the temp sensor in the rear of the right side head, shows the coolant temperature going up to 230°-240° before the thermostat opens, then goes down to what the manifold coolant temp gauge shows. No such spike in the temperature shows on that gauge. I'm not sure if that's caused by the restriction or not, the first couple of times I saw it, I was pretty concerned, but it always came back down, so I just ignored it. Still though, why does it do that?
We'll see if it still does that with the new AFR heads.