Technical 1951 8ba

I just picked this block up. Pretty much sight unseen, except for a few photos. I was told that it had some machine work to it already. I was excited to see that it had already been relieved. However, it’s not a relief job I am used to seeing. What do you think everyone?

 

What's unusual about that relief job???

 

I’m glad you said that, but I have never seen a relief job that went out around the valves before.


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Probably relieved that he got rid of it...Looks ok to me. Any cracks in the block?

 

I still have to have it checked myself, but per the seller. No cracks


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It’s bored out 1.25, so it’s on thin ice as it is.


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Did the seller say if it was sonic checked before boring? Pistons come with it to match the bore job?

 

No, and no. I’m currently looking for a shop that can sonic check it for me. It may turn out just fine. I have read that 1.25 can work, however that’s the end of the line for future rebuilds also.


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How do you know it’s the end of the line; you got a crystal ball? It’s not real unusual for a block to go to 3-3/8 which is another .060 over your .125. I run a 3-5/16 +.030 and have PERSONALLY seen 2 separate Flatmotor blocks go 1/4 in or .250. I cautioned my friend his was destined for”water everywhere” but 3 years later, NO PROBLEMS. Granted,that was 2 very unusual cases,but “weird, improbable” stuff can happen! Flatheads Forever! One of the “monster overbores” —- I took from a Ford F5( big truck); I bought it for the 4 in crank—-I was not expecting the 3-7/16 bore that had knurled pistons and NO SLEEVES—— yes, it went to the scrapper, but showed no water damage.

 

Let’s hope it all works out fine. I am new with the Flathead, this is my first one, and I’ve always been a glass half empty person. Actually, proving my lack of knowledge the only measurement I’ve taken of the block was laying a ruler across one of the cylinder bores, and it was at 3 3/8. I’d measure a lot more but it’s at my shop and we are currently closed for covid.


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Let's hope that you are lucky with this block. A lot of others have gone thru a few blocks before they got a good one.

 

Isn't that just a factory relief for a truck block?

 

It is an 1BA. That’s cast into the block.


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I went .125 over on my 8BA, very similar relief to your pics. Very drivable and no overheating issues. I used a merc crank and Ross had the pistons in stock.

 

Yeah, you mean .125 (1/8"), not "1.25". I'm with "Bandit Billy"; .125 over is usually no problem in an 8BA. I have done two this way myself with no problems. Hell, a lot of guys go to 3 3/8" with no problems. I also think the relief job looks fine (though I believe it to be unnecessary). If the block turns out to be crack free, I would say you done good. With that relief, you should do some head work to get back as much compression as possible (unless you are going to supercharge it).

On to more important things : "Flatheadjohn47"; why do you insist on posting pictures of your completely unusable intake manifolds on just about any thread about flatheads? It adds nothing to the thread, and may give some of the "newbies" wrong ideas. AND, I am personally sick and tired of seeing your unfinished '32 Cabriolet for years on end. Why don't you quit making those stupid manifolds and finish your (admittedly desirable) car?

 

Thanks man! Good info to know! I’ll stop stressing, and get building.


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Looks like a very usable block to me,,,,if it checks good,,,go for it .

And the 1BA cast in the back just means it was cast in. 51,,,,,it is still an 8BA series engine .
You probably got a good deal ,,,I don’t know how much you gave for it .

Tommy

 

300 dollars.. I was pretty happy with that price.


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Not bad at all,,,,,,do you plan to have it machined very much ?
I didn’t know if it has a fresh bore ,,,or if it needs a complete go over ?
Looks like it has been sitting a while,,,,,,but that could be light surface rust .
Freshly cleaned iron will rust in a few days if not coated with something .
As long as it is not pitted,,,,it won’t hurt it.

Tommy

 

In defense to flathead john's input, I would guess his photo's are from his file & not current....

 

My initial plan was either finding stock Merc crank and connecting rods. Or going with a Scat setup. Isky valve train and I really like the sound of the 400jr cam. Offenhauser heads and intake to match with dual 2brl. That’s the plan anyways.


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When I rebuilt the 8ba for my '39 p/u SoCal Speed Shop, https://www.socalsac.com had new rods which were just about the same price as have my old rods reconditioned, https://www.socalsac.com/Stock-Rod-7-Set-of-8-p/sflat001020.htm Just a thought.

 

Thank you! I put that into my saved parts folder.


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Read about squirt holes in Ford and Merc connecting rods here:
https://www.google.com/search?q=squ...ome..69i57.20711j0j4&sourceid=chrome&ie=UTF-8
The early engine didn't use squirt holes - just the splash system. So check your rods.

 

Lucky for me all I have is the bare block, I did not come with any internals .


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