Is there adifference between an "A" or "B" head gasket

[Jemelton#]

Due to a supplier mix up I think I will be receiving a head gasket for Model B instead of a Model A. Is there a significant difference between the two?
Thanks again for all of your help.

[quickchange]

Our newly produced one does both plus hi comp heads, copper

[Ron W]

I use a copper "B" gasket on my high compression "A" head with "A" block. I think it is the ideal combo! Ron W

[Charlie Stephens]

Originally Posted by Jemelton#

Due to a supplier mix up I think I will be receiving a head gasket for Model B instead of a Model A. Is there a significant difference between the two?
Thanks again for all of your help.

What head and what block are you running? Stock?

Charlie Stephens

[Cornishman]

I have a B block with an A head. Which gasket would I need?

[Ron W]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by forever4

What would make that ideal?

The gasket does not protrude into the combustion chamber as the head is shaped with more relief around the valves like the "B". Ron W

[Jemelton#]

It is a stock A block with a stock head. I guess I will just refuse the shipment and re- order from another supplier. Thanks guys, you are the best.

[Y-Blockhead]

Sooo, what is the difference between A and B head Gaskets?

[Jim Brierley]

The original B gaskets have a narrower than A "waist" area between the valves and the cyl. This made the gasket hang out into the A combustion chamber, not good. Not sure about modern B gaskets. The gasket must fit both the head and the block.

[CarlG]

Not sure why, but Snyder's instructions with their 5.5 A head say to use a B gasket.

[Y-Blockhead]

Originally Posted by CarlG

Not sure why, but Snyder's instructions with their 5.5 A head say to use a B gasket.

Yes Carl. And that is why it is confusing.

[Charlie Stephens]

Originally Posted by CarlG

Not sure why, but Snyder's instructions with their 5.5 A head say to use a B gasket.

My guess would be that the contact area between the head and the block more closely matches the B.

Charlie Stephens

[quickchange]

The A gasket can overhang the chamber around the valve area on hi comp head , not ideal , A B gasket does not , don,t ask how I know , check when installing 1st , just cause it fits the block does not mean it fits the head,

[James Rogers]

Originally Posted by Cornishman

I have a B block with an A head. Which gasket would I need?

Use a model A gasket and plug the steam holes in the middle of the deck.

[Cornishman]

Originally Posted by James Rogers

Use a model A gasket and plug the steam holes in the middle of the deck.

Thanks.

[tbirdtbird]

quickchange is dead on.
If any part of the gasket hangs into the combustion chamber, it will burn up and fail early.
The B gasket is scalloped out better around the valves to match the high compression heads, which have relief around the valve area for better breathing.

To run correctly , a motor needs
1. compression (head)
2. breathing (valves and cam)
3. timing (dizzy)

these 3 areas need careful attention
The dynamics of a running motor must be taken into account

carb is easy compared to above......

[quickchange]

James NO its a hi comp head ,cast snyders have less meat around back of valve area & normal felpro A will overhang, may not blow but will make engine sound harsh, I know , been there done that , do agree about blocking the two holes , but if using the B or our new one no problem,