The Ford Barn

Ken/Alabama · 10-12-2021, 04:22 PM

So which head gasket do I need to use on my stock 40 engine ?The one that match the block or the ones that match the head ?

flatjack9 · 10-12-2021, 05:21 PM

I'd use the one with round holes.

Ken/Alabama · 10-12-2021, 05:27 PM

Thanks Jack. I was gonna reach out to you about this.

petehoovie · 10-12-2021, 05:57 PM

Quote:

Originally Posted by Ken/Alabama

So which head gasket do I need to use on my stock 40 engine ?The one that match the block or the ones that match the head ?

Lawson Cox · 10-12-2021, 06:00 PM

I'd use the lower one myself. Larger holes allow more water flow. I know, more flow less flow debate has been going on for eons. That debate probably was started by the engine designers before designs went into production.

tubman · 10-12-2021, 07:39 PM

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I don't know much about this, as I am strictly an "8BA Guy", but isn't there a rule saying you should use the gasket that matches the block?

Phil Gillespie · 10-13-2021, 12:55 AM

My understanding is:
The trapezoid centre holes were initial gaskets in use. Then to better control water flow circulating through the block the gaskets with the round centre holes were introduced.
All in the way to keep better overall block temperature.
I am using the ones with round centre holes in a 59a engine, recent rebuild.
Phil NZ

Tinker · 10-13-2021, 01:02 AM

Just a thought. The water travels through the block and heads at the openings made, the gasket, unless the holes in the gasket are smaller to restrict flow, won't do much. So it makes since. Distribute or constrict the water flow. Always put the small hole to the front of the block, like on a yblock. If not it'll have no effect. Moving water to the back of the block is a good thing. On a 59a that would force water to the rest of the block. I don't know for certain it's better. I'll leave that up to everyone else.

Not sure but I'd guess the heads don't have trapezoids. Or at least I have not seen it. Doesn't mean it doesn't exist obliviously. It would not surprise me that I know everything. That's a joke by the way.

Bored&Stroked · 10-13-2021, 05:37 AM

Either one will work fine . . . though I tend to only use the ones with round holes.

From everything I know (which is not much - LOL), Ford decided to restrict the amount of water flow that too easily headed up to the center water outlets on the 39-42 engines . . . supposedly forcing more water to the other areas of the block - especially the rear. One example is the 39 - 42 Merc blocks - where they changed the center trapezoid water hole for a smaller round one.

They continued this quest when they made the 49-53 blocks - where they had much bigger water outlet holes in the rear of the block than in the front. As some have noted, almost all engines run hotter in the rear cylinders that the front cylinders . . . location, location, location . . .

10-12-2021, 05:21 PM	#2
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,526	Re: Head gasket question I'd use the one with round holes.

10-12-2021, 05:27 PM	#3
Ken/Alabama Senior Member Join Date: May 2010 Location: Alabama Posts: 3,257	Re: Head gasket question Thanks Jack. I was gonna reach out to you about this.

10-12-2021, 06:00 PM	#5
Lawson Cox Senior Member Join Date: May 2010 Location: Above the gnat line in Georgia Posts: 7,009	Re: Head gasket question I'd use the lower one myself. Larger holes allow more water flow. I know, more flow less flow debate has been going on for eons. That debate probably was started by the engine designers before designs went into production. __________________ Life is like a roll of toilet paper. The closer to the end, the faster it goes. It is better to be seen, than viewed. "We sleep safe in our beds because rough men stand ready in the night to visit violence on those who would do us harm".

10-12-2021, 07:39 PM	#6
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,303	Re: Head gasket question Sponsored Links (Register now to hide all advertisements) I don't know much about this, as I am strictly an "8BA Guy", but isn't there a rule saying you should use the gasket that matches the block?

10-13-2021, 12:55 AM	#7
Phil Gillespie Senior Member Join Date: Sep 2011 Location: Christchurch New Zealand Posts: 1,610	Re: Head gasket question My understanding is: The trapezoid centre holes were initial gaskets in use. Then to better control water flow circulating through the block the gaskets with the round centre holes were introduced. All in the way to keep better overall block temperature. I am using the ones with round centre holes in a 59a engine, recent rebuild. Phil NZ

10-13-2021, 01:02 AM	#8
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: Head gasket question Just a thought. The water travels through the block and heads at the openings made, the gasket, unless the holes in the gasket are smaller to restrict flow, won't do much. So it makes since. Distribute or constrict the water flow. Always put the small hole to the front of the block, like on a yblock. If not it'll have no effect. Moving water to the back of the block is a good thing. On a 59a that would force water to the rest of the block. I don't know for certain it's better. I'll leave that up to everyone else. Not sure but I'd guess the heads don't have trapezoids. Or at least I have not seen it. Doesn't mean it doesn't exist obliviously. It would not surprise me that I know everything. That's a joke by the way. Last edited by Tinker; 10-13-2021 at 01:48 AM.

10-13-2021, 05:37 AM	#9
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,062	Re: Head gasket question Either one will work fine . . . though I tend to only use the ones with round holes. From everything I know (which is not much - LOL), Ford decided to restrict the amount of water flow that too easily headed up to the center water outlets on the 39-42 engines . . . supposedly forcing more water to the other areas of the block - especially the rear. One example is the 39 - 42 Merc blocks - where they changed the center trapezoid water hole for a smaller round one. They continued this quest when they made the 49-53 blocks - where they had much bigger water outlet holes in the rear of the block than in the front. As some have noted, almost all engines run hotter in the rear cylinders that the front cylinders . . . location, location, location . . .