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10-04-2023, 04:11 AM | #1 |
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1939 heads on 59AB engines
A question for the Flathead pros:
was it common back in the days to use 1939 heads on stock (not bored) 59AB engines? thx |
10-04-2023, 06:55 AM | #2 |
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Re: 1939 heads on 59AB engines
You can but the valve pockets will need to be opened up a tad to clear the valves. Not the depth but around the edge. KR Wilson made a fixture with a cutter for this.
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10-04-2023, 07:18 AM | #3 |
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Re: 1939 heads on 59AB engines
I have done several 81 heads to fit the 59ab using the kr wilson fixture--I do have the fixture
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10-04-2023, 07:19 AM | #4 |
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Re: 1939 heads on 59AB engines
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10-04-2023, 07:27 AM | #5 |
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Re: 1939 heads on 59AB engines
Here’s a photo of it
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10-04-2023, 08:08 AM | #6 |
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Re: 1939 heads on 59AB engines
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10-04-2023, 08:47 AM | #7 |
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Re: 1939 heads on 59AB engines
KRWilson 6050 B1
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10-04-2023, 08:48 AM | #8 |
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Re: 1939 heads on 59AB engines
Depending on what cam you're using, you may need to do more than just the eyebrow radius at the top of the chambers. Once you get the upper radius areas done, then check to make sure you have clearance above the valves (up at the top of the chamber). The valves are canted in a manner that causes most clearance problems to be at the top of the valve (where they are the highest above the deck surface).
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10-04-2023, 10:07 AM | #9 |
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Re: 1939 heads on 59AB engines
__________________
The only thing nice about being imperfect is the joy it brings to others.... "Silver rings, your butt! Them's washers!" "We shot our way out of that town for a dollar's worth of steel holes!" - from 'The Wild Bunch' - 1969 https://www.youtube.com/watch?v=7NReUd2_0u0 |
10-04-2023, 10:15 AM | #10 |
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Re: 1939 heads on 59AB engines
What is the purpose of using early heads for a lower horse power engine on a higher horse power (239 CID) engine.? It would appear to me that this would be a step backwards.
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10-04-2023, 11:53 AM | #11 | |
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Re: 1939 heads on 59AB engines
Quote:
Compression ratio! Coop . |
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10-04-2023, 11:59 AM | #12 | |
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Re: 1939 heads on 59AB engines
Quote:
One of the most important things is to also tune the "squish" (piston to head clearance) to .040 to .045. Having a tight squish is super important for overall performance (on any flathead engine). |
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10-04-2023, 07:31 PM | #13 |
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Re: 1939 heads on 59AB engines
The post war 59A heads have smaller chambers than the prewar 81A heads. The last center water outlet heads, the 59A-B, have slightly smaller chambers still. Sticking to post war heads is higher compression options.
The head chamber sizes are very well listed in the pdf available in the first post of this thread: https://www.fordbarn.com/forum/showthread.php?t=4336 |
10-05-2023, 08:13 AM | #14 |
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Re: 1939 heads on 59AB engines
Thanks a lot for the feedback.
The reason for my question is that I have Canadian aluminium heads C 91A-6050-B in great condition. |
10-05-2023, 11:51 AM | #15 |
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Re: 1939 heads on 59AB engines
Thanks to Bored Stroked for the detailed explanation:
The 59AB engine in my '36 was rebuilt in 1960 by a local machinist that specialized in engines for stock car racers in lieu of drag racing. The original rebuild was done in '54 by a shop in SLC that specialized in drag racing.. It had Offy 10.1 heads and therefore would not run on anything but premium..Not at all a good combination for everyday driving. The second rebuild involved a larger bore, new pistons and modified 59AB heads. As I recall the machinist told me he 'milled, domed and flycut' the heads. The engine has always ran very well.
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10-14-2023, 01:21 PM | #16 |
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Re: 1939 heads on 59AB engines
these are the polished beauties!
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10-14-2023, 03:50 PM | #17 |
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Re: 1939 heads on 59AB engines
__________________
The only thing nice about being imperfect is the joy it brings to others.... "Silver rings, your butt! Them's washers!" "We shot our way out of that town for a dollar's worth of steel holes!" - from 'The Wild Bunch' - 1969 https://www.youtube.com/watch?v=7NReUd2_0u0 |
10-15-2023, 04:35 AM | #18 |
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Re: 1939 heads on 59AB engines
Those are very shiny heads!
I would check and see if the valve area already has been clearanced for use on a post war block. If not find someone in your area with the KR Wilson tool made to do that. It would help if you included your general location in your signature. For example I have a valve clearance tool, live in the Houston area, and visit the San Antonio and Austin areas on occasion. |
10-15-2023, 05:43 PM | #19 |
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Re: 1939 heads on 59AB engines
Now that all that polishing is done, you should "spot face" the tops of the stud holes in the heads - to give you a nice, even, flat surface for the hardened washers to ride against.
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10-16-2023, 04:23 AM | #20 |
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Re: 1939 heads on 59AB engines
Thanks a lot guys for the great feedback.
Yes - I have to flat the tops of the stud holes. |
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