The Ford Barn

Ole Lou · 01-28-2013, 06:24 PM

I have a set of 29A heads on a 1947 59 flathead. Understand 29A were used on 42 Mercury flathead. Are these heads lower compression than the 59AB heads? Were they used for any other year applications?

rotorwrench · 01-28-2013, 08:03 PM

1942 239 cid heads would have been used on big trucks, Mercury cars, and some special orders requesting 95 HP motors. They should be pretty close to the same as the 59A since the 59A was patterened after the wartime 239 production and wartime stuff was basically 1942 stuff carried forward. I'm sure there would only be subtle differences. Compression ratios should be about the same.

The block was where most of the difference was.

Ole Lou · 01-28-2013, 08:31 PM

thanks for the info

41ford1 · 01-29-2013, 08:11 AM

Here is what is in the TSBs dated 2-6-42, page15 subject 6000:

29A heads 6.4:1 CR, 78-80cc chamber volume
If you want a higher CR find a set of these:
19AS Heads 7.1:1 CR, 70-72 cc, or 81AS heads 8.1:1, 60-62 cc, or 99AS heads 7.6:1 CR, 65-67cc. All of these were applied to Mercury 100HP rated engines. All used domed pistons.

The 59A heads are 6.75:1 CR. I did not find the volume for these.

Walt Dupont--Me. · 01-29-2013, 08:49 AM

Quote:

Originally Posted by 41ford1

Here is what is in the TSBs dated 2-6-42, page15 subject 6000:

29A heads 6.4:1 CR, 78-80cc chamber volume
If you want a higher CR find a set of these:
19AS Heads 7.1:1 CR, 70-72 cc, or 81AS heads 8.1:1, 60-62 cc, or 99AS heads 7.6:1 CR, 65-67cc. All of these were applied to Mercury 100HP rated engines. All used domed pistons.

The 59A heads are 6.75:1 CR. I did not find the volume for these.

Good info 41ford1. Do you know what the AS stand for? I alway thought the 81 heads only came on 38 engine 24 stud. I know thay were the smallest CC. I could be wrong, ask my wife. Walt

41ford1 · 01-29-2013, 10:09 AM

Sponsored Links (Register now to hide all advertisements)

Walt,
The manual did not define the AS. It just listed the head #s with the comp ratios and HP ratings. You be wrong? Don't believe it.

rotorwrench · 01-29-2013, 02:10 PM

I'm including a link to the HAMB where the late great Blown49 has his list for near all relevant flathead heads that are more available. http://www.jalopyjournal.com/forum/s...ression+ratios

A lot depends on the size of the pistons for this and that's why it has a chart in the link on post #2 by Ryan.

The 29A heads were 6.56:1 heads with stock 3 3/16" pistons. The 59A is only slightly higher at 6.76:1.

The AS marked heads are also known as "Denver" heads or high altitude heads and they are kind of rare now days.

Bruce Lancaster · 01-29-2013, 02:26 PM

There were 3 AS Heads for 221 and 239, the S probably means something like "Special"...these heads were over-the counter ones not used on production cars, listed for natural gas or high altitude applications. The 81AS ones were highest comp, 60 CC...the 81AS should not be confused with regular 81A which is much larger volume.
For production heads 29A 78-80 cc, 59A 77-79, 59AB 73.5-75.5.
The 29 heads are for prewar valve angle and need to be slightly reworked where valve pockets meet the block to be used safely on 59 and later engines.
Many of the oddball heads like the several AS heads are not in the final collection of specs in the bulletins.
I found an elderly Canadian bulletin that listed a very wide range of heads including USA production heads, the S heads, and the many Canada only heads with specs figured for both 221 and 239 for all the 24 stud ones...that chart supplied some of the numbers for Blown49's extremely useful chart.

01-28-2013, 06:24 PM	#1
Ole Lou Senior Member Join Date: May 2010 Posts: 239	29A Heads I have a set of 29A heads on a 1947 59 flathead. Understand 29A were used on 42 Mercury flathead. Are these heads lower compression than the 59AB heads? Were they used for any other year applications?

01-28-2013, 08:31 PM	#3
Ole Lou Senior Member Join Date: May 2010 Posts: 239	Re: 29A Heads thanks for the info

01-29-2013, 08:11 AM	#4
41ford1 Senior Member Join Date: May 2010 Location: ManchVegas, New Hampshah Posts: 1,589	Re: 29A Heads Here is what is in the TSBs dated 2-6-42, page15 subject 6000: 29A heads 6.4:1 CR, 78-80cc chamber volume If you want a higher CR find a set of these: 19AS Heads 7.1:1 CR, 70-72 cc, or 81AS heads 8.1:1, 60-62 cc, or 99AS heads 7.6:1 CR, 65-67cc. All of these were applied to Mercury 100HP rated engines. All used domed pistons. The 59A heads are 6.75:1 CR. I did not find the volume for these. Last edited by 41ford1; 01-29-2013 at 08:27 AM. Reason: Added 59 CR

01-29-2013, 10:09 AM	#6
41ford1 Senior Member Join Date: May 2010 Location: ManchVegas, New Hampshah Posts: 1,589	Re: 29A Heads Sponsored Links (Register now to hide all advertisements) Walt, The manual did not define the AS. It just listed the head #s with the comp ratios and HP ratings. You be wrong? Don't believe it.

01-29-2013, 02:10 PM	#7
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,431	Re: 29A Heads I'm including a link to the HAMB where the late great Blown49 has his list for near all relevant flathead heads that are more available. http://www.jalopyjournal.com/forum/s...ression+ratios A lot depends on the size of the pistons for this and that's why it has a chart in the link on post #2 by Ryan. The 29A heads were 6.56:1 heads with stock 3 3/16" pistons. The 59A is only slightly higher at 6.76:1. The AS marked heads are also known as "Denver" heads or high altitude heads and they are kind of rare now days.

01-28-2013, 08:03 PM	#2
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,431	Re: 29A Heads 1942 239 cid heads would have been used on big trucks, Mercury cars, and some special orders requesting 95 HP motors. They should be pretty close to the same as the 59A since the 59A was patterened after the wartime 239 production and wartime stuff was basically 1942 stuff carried forward. I'm sure there would only be subtle differences. Compression ratios should be about the same. The block was where most of the difference was.

01-29-2013, 02:26 PM	#8
Bruce Lancaster Member Emeritus Join Date: May 2010 Location: Madison, NJ Posts: 5,230	Re: 29A Heads There were 3 AS Heads for 221 and 239, the S probably means something like "Special"...these heads were over-the counter ones not used on production cars, listed for natural gas or high altitude applications. The 81AS ones were highest comp, 60 CC...the 81AS should not be confused with regular 81A which is much larger volume. For production heads 29A 78-80 cc, 59A 77-79, 59AB 73.5-75.5. The 29 heads are for prewar valve angle and need to be slightly reworked where valve pockets meet the block to be used safely on 59 and later engines. Many of the oddball heads like the several AS heads are not in the final collection of specs in the bulletins. I found an elderly Canadian bulletin that listed a very wide range of heads including USA production heads, the S heads, and the many Canada only heads with specs figured for both 221 and 239 for all the 24 stud ones...that chart supplied some of the numbers for Blown49's extremely useful chart.