Question on head gasket and oil additive

[55 Chevy]

The bore size on a new # 3995633 is 3.980. This gasket was used for the 307 motor,is steel shim & has a coating on it.
As far as I know G.M. has discontinued this gasket.
Not sure of the Fel Pro cross over #.

There are a couple of smaller bore gaskets G.M. # 14085906@ 3.875 & # 462690@ 3.875. They are both steel shim & have no coating on them.Also no longer available.


Just curious,what is the exact bore size of your motor?

Allan

[Nova4301]

Originally Posted by 55 Chevy

The bore size on a new # 3995633 is 3.980. This gasket was used for the 307 motor,is steel shim & has a coating on it.
As far as I know G.M. has discontinued this gasket.
Not sure of the Fel Pro cross over #.

There are a couple of smaller bore gaskets G.M. # 14085906@ 3.875 & # 462690@ 3.875. They are both steel shim & have no coating on them.Also no longer available.


Just curious,what is the exact bore size of your motor?

Allan

I am building a 307 .060 over. 3.935 is my bore size, so that GM #3995633 would be perfect, but if it is not avaliable then I will have to find a gasket with similar specs.

In case anyone is curious, I found the Fel-pro replacement head gasket for the 307 GM#3995633. It is a Fel-Pro #7733SH1 and it is the same except the bore size is 4.100.

Myron, do you run the 0W-30? and how does the Amsoil racing oil compare...I didn't see a 0W-30 racing oil?

[Alan Roehrich]

Cometic will make gaskets for you, to your specifications. They are certainly pricey, as much as $200 for a set. But if you are careful, you can reuse them 2-3 times, or more. If you give them a bore size and a thickness, they'll be close to dead on. Mine have not varied more than 0.005" on bore size (always big, not small) and no more than 0.002" on thickness (always thick, not thin).

[big blue galaxie]

The motor oil is now named Amsoil Signature Series 0W30. The also have a 0W20.

[Myron Piatek]

Originally Posted by big blue galaxie

The motor oil is now named Amsoil Signature Series 0W30. The also have a 0W20.

Those are not the same oils. The Dominator Series is new as of last year and are fortiufied more for the racing environment. The Signature Series 0W-30 may have gotten reformulated a year or two ago. I'm only speculating, but it may have to do with newer model emission regulations and compatibility, similar to a new diesel formulation for 2007 & newer diesel trucks. I believe the zinc content has something to do with it. The race oils, older diesel, including the HDD 5w-30, and some of the others, still have a large amount of zinc and similar additives. It's all good stuff nonetheless.

[james schaechter]

I would have to agree with Alan on the head gaskets. I have used Cometics on our 283 and 327s and reuse them 3 times, then I take them off and save them. I probably could use them again. They get pretty reasonable when you get to use them more than once. You tell them the bore size and thickness and they take care of it.

[big blue galaxie]

Originally Posted by Myron Piatek

Those are not the same oils. The Dominator Series is new as of last year and are fortiufied more for the racing environment. The Signature Series 0W-30 may have gotten reformulated a year or two ago. I'm only speculating, but it may have to do with newer model emission regulations and compatibility, similar to a new diesel formulation for 2007 & newer diesel trucks. I believe the zinc content has something to do with it. The race oils, older diesel, including the HDD 5w-30, and some of the others, still have a large amount of zinc and similar additives. It's all good stuff nonetheless.

The product I was referring to was either the Series 2000 (or might be 3000) and they are a different product line from the Dominator series; it looks like they renamed it but I have to check with tech to verify it. And you know that the chemistry will work either way.

[Tim H]

Castrol also frowns on using any additives with their oil. As the rep stated " why undo something that our chemists have engineered into our oil ?"

[House of Darts]

Mobil/ Mobil 1 makes the base oils for all synthetic oils. I used to sell race oils. When you read the specs for synthetic motor oil and compare them all, this is what you will find: everyone has a hard one for additives that makes their oil different. When you look very close, many are only slightly different competitors to Mobil 1. They really only offer slight advantages. Most are only noticeable in lab reports. SAVE YOUR MONEY. Brad penn 0-30,10-30 semi synthetic and Valvolone VR1 are the best for the $ spent. Amsoil does offer a oil analisys that will answer any questions about the oil you are using. They contract with a private company. You can deal with this company direct. OH BY THE WAY, ask 50 racers about oil and you'll get 53 answers.