The Ford Barn

BButturff · 05-06-2026, 04:22 PM

When I bought my Model A eighteen months ago I had no idea what cylinder head it had so I wasn't looking to buy one. But I remember them being readily available at Snyder's, Mike's, Bert's, Model A Medic, etc. So now that I know I have a stock head and I'm looking for a 5.5:1 head they've been "temporarily out of stock" for many months.

Anybody out there have an idea why this is? Are they no longer being produced?

Y-Blockhead · 05-06-2026, 04:28 PM

I see Snyder's has the 6.0 in stock. Maybe they are phasing out the 5.5 since they are almost the same CR and I believe made by the same person.

https://www.snydersantiqueauto.com/p...8622&cat=41686

47topless · 05-06-2026, 04:32 PM

Check with your favorite local machine shop and inquire as to having your head milled to your specifications.

Y-Blockhead · 05-06-2026, 04:37 PM

Quote:

Originally Posted by 47topless

Check with your favorite local machine shop and inquire as to having your head milled to your specifications.

Not a good idea...

Keith True · 05-06-2026, 04:49 PM

You can't mill an A head to gain anything.The high-compression head has a whole different combustion chamber design.Some call it a heart shaped design.I don't have any pictures,but folks on here have posted the stock and high compression designs side by side.

BButturff · 05-06-2026, 05:08 PM

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Quote:

Originally Posted by Y-Blockhead

I see Snyder's has the 6.0 in stock. Maybe they are phasing out the 5.5 since they are almost the same CR and I believe made by the same person.

https://www.snydersantiqueauto.com/p...8622&cat=41686

That's probably what's going on. I had the 5.5 head marked on my wish lists so wasn't looking for anything else. Thanks!

47topless · 05-06-2026, 06:11 PM

Quote:

Originally Posted by Keith True

You can't mill an A head to gain anything.The high-compression head has a whole different combustion chamber design.Some call it a heart shaped design.I don't have any pictures,but folks on here have posted the stock and high compression designs side by side.

Good to know. I went the mill route with my V8 heads, and it worked great, but the A head is another animal. Thanks for the clarification.

emf · 05-06-2026, 06:47 PM

If you have an interest in a high compression head, contact Terry Burtz since he has a very good one available and I believe they are in stock. burtzblock.com

Frank

Synchro909 · 05-06-2026, 07:06 PM

If you were considering a 5.5:1 head, a 6:1 head will not be much different. You would have a little more grunt at the bottom end of the rev range but that is about it. Just make sure you reduce the amount of ignition advance - too much is what kills bearings (and other things in there)

Klattu1929 · 05-06-2026, 08:12 PM

I put a Burtz head on and I am very impressed; my engine is .100 over. I also installed an automatic advance in the valve chamber. Limit my total advance to about 25-26 deg. engine runs great, plenty of power. Make sure your main and rod bearings are adjusted. I have a couple stock heads, and they are just dust collectors now.

Jim/GA · 05-06-2026, 10:34 PM

Quote:

Originally Posted by Y-Blockhead

I see Snyder's has the 6.0 in stock. Maybe they are phasing out the 5.5 since they are almost the same CR and I believe made by the same person.

https://www.snydersantiqueauto.com/p...8622&cat=41686

No. Snyder's makes both heads, they will keep selling both.

They make them in batches. You have to wait for the time for casting, transportation, machining, etc. They will be back in stock eventually.

I recommend the 5.5 over the 6.0 head for the average driver with average original engine. It is very easy to get engine knock with the 6.0 head, and then your bearings will go south.

BButturff · 05-07-2026, 06:50 AM

Quote:

Originally Posted by Jim/GA

I recommend the 5.5 over the 6.0 head for the average driver with average original engine. It is very easy to get engine knock with the 6.0 head, and then your bearings will go south.

I have heard or read this exact thing before. Although my engine was rebuilt fairly recently I don't know if it still has babbitt bearings or if it has been converted to insert bearings. Unfortunately, the family of the previous owner was no help in answering this question. My engine starts, idles and runs very well so I'm not yet willing to open it up just to find out.

alexiskai · 05-07-2026, 07:03 AM

Quote:

Originally Posted by BButturff

I have heard or read this exact thing before. Although my engine was rebuilt fairly recently I don't know if it still has babbitt bearings or if it has been converted to insert bearings.

Why would that make a difference in this context?

BButturff · 05-07-2026, 07:19 AM

Quote:

Originally Posted by alexiskai

Why would that make a difference in this context?

Since there were valid suggestions of using a Snyder's 6.0 head or even the Burtz 6.5 head I felt compelled to explain why I don't consider them to be an option at this time. If and when I pull the pan off of my engine and discover insert bearings I would consider them.

alexiskai · 05-07-2026, 07:42 AM

Quote:

Originally Posted by BButturff

Since there were valid suggestions of using a Snyder's 6.0 head or even the Burtz 6.5 head I felt compelled to explain why I don't consider them to be an option at this time. If and when I pull the pan off of my engine and discover insert bearings I would consider them.

The idea that Babbitt bearings can’t handle higher compression is a myth.

BButturff · 05-07-2026, 08:06 AM

Quote:

Originally Posted by alexiskai

The idea that Babbitt bearings can’t handle higher compression is a myth.

If it really is a myth I would appreciate any and all evidence to prove it so. Until then I can't take a chance on a Model A that I'll be handing down to my grandson some day.

BButturff · 05-07-2026, 08:14 AM

Quote:

Originally Posted by alexiskai

The idea that Babbitt bearings can’t handle higher compression is a myth.

Randall Strickland, you've poured your fair share of babbitt for T's and A's. What's your opinion about babbitt and higher compression?

Big hammer · 05-07-2026, 08:29 AM

Babbitt can’t handle high compression ??? Tell that to diesel engines that have babbitt bearings ! way more compression than a measly little 6.0 6.5 7.0 compression

Fullraceflathead · 05-07-2026, 09:29 AM

Some of the large diesels have babbitt bearings in them and they have compression ratios around 18.5-1!!!

Bob Bidonde · 05-07-2026, 09:40 AM

I have been running 5.5:1 and 6:1 compression ratio cylinder heads for many years successfully with Babbitt bearings. By the way, the bearing diameter determines the amount of bearing stress in the Babbitt due to cylinder combustion pressures and inertial forces.
It makes good business sense if the 5.5:1 head was discontinued because of the 6:1 head. The difference between them is only 3%.

05-06-2026, 04:22 PM	#1
BButturff Senior Member Join Date: Oct 2024 Location: The driftless area of SE Minnesota Posts: 214	New 5.5:1 Cylinder Head Availability When I bought my Model A eighteen months ago I had no idea what cylinder head it had so I wasn't looking to buy one. But I remember them being readily available at Snyder's, Mike's, Bert's, Model A Medic, etc. So now that I know I have a stock head and I'm looking for a 5.5:1 head they've been "temporarily out of stock" for many months. Anybody out there have an idea why this is? Are they no longer being produced? __________________ _______________________ The other Bruce in Minnesota 1931 Model A Closed Cab (Budd) Pickup "Aurora" Model A Ford Club of America Lady Slipper A's "You can't go back and change the beginning, but you can start where you are and change the ending." - C.S. Lewis

05-06-2026, 04:28 PM	#2
Y-Blockhead Senior Member Join Date: Jul 2011 Location: Redondo Beach, CA Posts: 7,288	Re: New 5.5:1 Cylinder Head Availability I see Snyder's has the 6.0 in stock. Maybe they are phasing out the 5.5 since they are almost the same CR and I believe made by the same person. https://www.snydersantiqueauto.com/p...8622&cat=41686

05-06-2026, 04:32 PM	#3
47topless Senior Member Join Date: Jun 2022 Location: Northern Colorado Posts: 496	Re: New 5.5:1 Cylinder Head Availability Check with your favorite local machine shop and inquire as to having your head milled to your specifications.

05-06-2026, 04:49 PM	#5
Keith True Senior Member Join Date: May 2010 Location: Epping N.H. Posts: 3,689	Re: New 5.5:1 Cylinder Head Availability You can't mill an A head to gain anything.The high-compression head has a whole different combustion chamber design.Some call it a heart shaped design.I don't have any pictures,but folks on here have posted the stock and high compression designs side by side.

05-06-2026, 06:47 PM	#8
emf Senior Member Join Date: Mar 2013 Location: Hudson, NY Posts: 580	Re: New 5.5:1 Cylinder Head Availability If you have an interest in a high compression head, contact Terry Burtz since he has a very good one available and I believe they are in stock. burtzblock.com Frank

05-06-2026, 07:06 PM	#9
Synchro909 Senior Member Join Date: Jun 2014 Location: Melbourne, Australia Posts: 8,432	Re: New 5.5:1 Cylinder Head Availability If you were considering a 5.5:1 head, a 6:1 head will not be much different. You would have a little more grunt at the bottom end of the rev range but that is about it. Just make sure you reduce the amount of ignition advance - too much is what kills bearings (and other things in there) __________________ When all is said and done, more is said than done. That's why we judge people on what they do, not what they say. I sometimes wonder what happened to the people who asked me for directions. If I am not in trouble, I've done something wrong.

05-06-2026, 08:12 PM	#10
Klattu1929 Member Join Date: May 2023 Location: Washington State Posts: 93	Re: New 5.5:1 Cylinder Head Availability I put a Burtz head on and I am very impressed; my engine is .100 over. I also installed an automatic advance in the valve chamber. Limit my total advance to about 25-26 deg. engine runs great, plenty of power. Make sure your main and rod bearings are adjusted. I have a couple stock heads, and they are just dust collectors now.

05-07-2026, 08:29 AM	#18
Big hammer Senior Member Join Date: Jun 2014 Location: Land of Lincoln Posts: 3,632	Re: New 5.5:1 Cylinder Head Availability Babbitt can’t handle high compression ??? Tell that to diesel engines that have babbitt bearings ! way more compression than a measly little 6.0 6.5 7.0 compression __________________ Don't force it with a little hammer tap, tap, tap get a bigger hammer tap done

05-07-2026, 09:29 AM	#19
Fullraceflathead Senior Member Join Date: May 2012 Location: Chillicothe, Missouri Posts: 1,851	Re: New 5.5:1 Cylinder Head Availability Some of the large diesels have babbitt bearings in them and they have compression ratios around 18.5-1!!! __________________ "If I asked people what they wanted they would have said faster horses." -Henry Ford "Primitive technology is not a design flaw" 1928 Ford Model A Roadster Pickup 1930 Gordon Smith Air Compressor 1941 Willy's Pickup 1960 Thunderbird-For Sale 1964 Buick Riviera 2x4 425 1965 Pontiac GTO, 455 Super Duty 2004 Dodge Ram SRT-10, V-10 Viper 1977 Charger Jet Boat,460 Ford,Jacuzzi Jet Front Engine Nostalgia Dragster,Supercharged 296 "Fullrace Flathead" Ford Engine Build up on DVD ask

05-07-2026, 09:40 AM	#20
Bob Bidonde Senior Member Join Date: May 2010 Location: Long Island, NY Posts: 4,383	Re: New 5.5:1 Cylinder Head Availability I have been running 5.5:1 and 6:1 compression ratio cylinder heads for many years successfully with Babbitt bearings. By the way, the bearing diameter determines the amount of bearing stress in the Babbitt due to cylinder combustion pressures and inertial forces. It makes good business sense if the 5.5:1 head was discontinued because of the 6:1 head. The difference between them is only 3%. __________________ Bob Bidonde Last edited by Bob Bidonde; 05-07-2026 at 09:49 AM.