8BA head mismatch-I should probably fix

[markdtn]

On my 8BA in an 8N tractor I have an 8BA head on the right and an EAB head on the left. The machine shop that I used gave me the EAB head because the LH 8BA had a crack. It's been running fine for almost 10 years now, but from what I am reading, I think I should probably find a match. Seems like the EAB is a more desirable head. Not seeing any RH EABs on Evilbay right now but I do see some (pairs) of EAC Mercury heads. Of course, these are heavy and shipping is expensive.

So some questions: 1-is this even worth worrying about? 2-Is EAC equivalent to EAB? 3-I assume cracks are a real concern on used heads or not usually?

When I built it, I used a stud kit for aluminum heads but I just can't see paying up for those. I don't need more power, it's scary enough as it is. Thanks for your advice.

[marko39]

If it runs fine I wouldn’t mess with it!

[hueyhoolihan]

Originally Posted by marko39

If it runs fine I wouldn’t mess with it!

my thoughts too. i WISH i had an old engine that ran reliably for ten years!

in fact if i knew the perfectly matched heads on my v8 would run reliably for ten years if i installed a mismatched set, i think i might do it. ha

[Mart]

Some things are not worth worrying about. This is one of them. Congrats on a good running trouble free combo!

[markdtn]

Sounds like leave it alone then. So the volume is similar on both 8BA and EAB heads?

[Mart]

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I don't know about the volume, and I'm not saying you should change anything, but in the interest of science, why not do a compression test? It would be interesting to see if there is a discernible difference that can be associated with each bank. Or it might be that the difference is lost within normal variances between cylinders on an old engine. I'd be interested in the results.
I am the guy with an engine that has seven 30 over bores and one 60 over bore by the way!
Mart.

[hueyhoolihan]

Originally Posted by Mart

I don't know about the volume, and I'm not saying you should change anything, but in the interest of science, why not do a compression test? It would be interesting to see if there is a discernible difference that can be associated with each bank. Or it might be that the difference is lost within normal variances between cylinders on an old engine. I'd be interested in the results.
I am the guy with an engine that has seven 30 over bores and one 60 over bore by the way!
Mart.

i like to recognize talent when i see it and when it is deserved...

you know...i've been looking at the pic in your signature for about a year now, and just realized that it's the combustion chamber of a head intentionally making good use of shadow. i thought it a some sort of post-expressionist portrait...truly inventive and a real work of art!

i have to know...is the pic your inspiration or did you find it somewhere?

[Mart]

Ha ha Hi Huey. It was just a pic I found online many years ago. It's a Y block head with a crack in it. The human brain automatically "recognises" faces even if it isn't really a face. I like that it appears to be looking at the thread.
Mart.

[hueyhoolihan]

Originally Posted by Mart

Ha ha Hi Huey. It was just a pic I found online many years ago. It's a Y block head with a crack in it. The human brain automatically "recognises" faces even if it isn't really a face. I like that it appears to be looking at the thread.
Mart.

thanks...

i find that type of "taken out of context and it's something else entirely" type of artwork captivating.

my father was a shop teacher and his students used a piece of plywood under their projects to protect the workbench from overspray and general abuse. as you can imagine, over the years many layers of accretion revealed themselves from time to time creating quite a complex image. my father framed it and hung it on the wall at home. and you wouldn't believe how many people thought it a remarkable piece of artwork.

anyway...kudos on recognizing its value.

[51504bat]

Just in case you think about swapping both heads for Merc's cause you got a deal on them, think again. Merc heads on a 3 3/4" stroke 8ba is a step backward.

[markdtn]

OK. Thanks. I will do a compression test and report back. I was reading that EAB engines had 7.2:1 compression ratio while 8BA was 6.8. 69-71cc vs: 75-77cc. Just thought that it might be too much of an imbalance. I'm not looking for power, only want smooth and cool running.

https://myflatheadford.com/know-your-1948-1953-head/
https://myflatheadford.com/decoding-flathead-v8-heads/

[John Gibson]

As an old guy in Maine once told me, “If it ain’t broke, don’t fix it”!

[Zax40]

Just saw a set of EAB heads for sale last weekend at the NEGA swap meet. The seller still has them. I can try to track down his contact info if you are interested.

[mfirth]

Yes leave it be. John Gibson says it all.

[tubman]

I would change that old saying to : "If it ain't broke in any way don't fix it, but if it's not perfect, at least take a look at it". In this case, I would wait and see what a compression test shows. If there is no significant difference between sides, the plugs would go back in; if there is, the head would come off. The only problem is if the low readings are on the EAB side.

After all, we are car guys, and as such, a step above the average "back yard mechanic".

[rotorwrench]

While EAB heads were designed to give a bit better performance, it is getting harder to find known to be good used heads. EABs used to be available NOS with no tampering but folks tend to like to skim those heads to get even more compression. Most sellers wouldn't know if it was ever shaved or not and buyers are in the same boat. I've purchased some that were cut clear down to the bottoms of the thermostat pockets. 8BA and EAB are both safe heads to get as long as a person checks the piston to dome clearance to keep it at .050" or more clearance. I don't like shimming heads with more than one gasket but I know folks that have done that.

Mercury 8CM /EAC and truck 8RT stuff are made to lower compression so they won't help much for power. Merc 255s have the longer stroke so they needed that to keep the ratio similar to the smaller 239 engines and trucks just had to be able to pull max power with reliability.

[1942deluxe]

I have an 8BA L.H. head that I'm pretty sure is NOS that was in the basement of my Ford dealership I closed in 2004 if you wanted to go that route. I'm sure the shipping would be excessive though.

[markdtn]

I will do a compression test over the weekend and report back.

[Christopher Salty]

Put a set of Edelbrock aluminum heads PN 1115 on there gives a compression ratio of about 8:1. Maybe shave them down a bit to get a squish of 0.050 and get compression up to about 8.25:1.

[GB SISSON]

Originally Posted by Christopher Salty

Put a set of Edelbrock aluminum heads PN 1115 on there gives a compression ratio of about 8:1. Maybe shave them down a bit to get a squish of 0.050 and get compression up to about 8.25:1.

You might want to consider 'wheelie bars' if you make this mod. As far as balanced compression on both sides, there are videos of our V8s running quite nicely with one head removed entirely.