Technical Banger Head I.D. & Thoughts Wanted

I was going to post this in the monthly Banger Thread, but I didn’t want to muck it up with a bunch of pics and dumb questions.

I have a relatively stock 29 Model A engine. I think it has been rebuilt at some time as it is bored .080” over and the cylinder walls look amazing, with no ridges. Here it is.


I have converted to 12 volts, installed an FSI electronic dizzy with centrifugal advance, Champion plugs and a Marvel carb. Runs great… but of course I’d like s’more get up. So here goes…

I recently acquired these two heads and have some questions about them.

1st – I can’t find much info on this one. The combustion chamber design looks stock to me. Would it provide any gains over the stock head? Do you know anything about this design? If it is better than stock, what head gasket would be best?



2nd – This one, I have found some info about it and it may be a decent performer. It does have a crack BUT, it’s between two water jacket holes. Would this be a problem or no big deal?

The date on the left reads 4-21-33




My biggest concern is that the previous owner milled it down to try to get rid of crack (???) and in doing so, leveled the combustion side.


Here is a pic showing what the underside should look like


Looking at the picture of my engine posted above, the pistons do not protrude past the top of the block. SO…

Is this head a good candidate to install or should I hang it on the wall?

If it’s good to go… What head gasket(s) should I use?

Any idea of what the compression ratio would be?

Would it require a more “built” engine than mine?

Driving conservatively, is there a good chance I’d kill my mains, which are most likely babbit?

Thanks for your time!!!

 

You can go up to 7:1 compression. And it won't hurt your Babbitt. 7:1 will change your car from a putt putt to drivable

 

This is the best head gasket I have found so far.

https://www.brattons.com/model-a-composite-gasket-by-best-gasket.html

 

You will find out a lot as you search, but for starters, recheck the pop-up. You will need (double check my specs) .035" clearance from piston to head. If I remember correctly, the average compressed height of the head gasket is about .047". There is a cc chart to calculate CR. Speedway Motors sells a good inexpensive cc measuring system. The smaller the squish height on a banger, the better the head will work for you, considering you have adequate room around the valves and adequate room for the gasses to travel easily from the valves and over the deck and into and out of the cylinders.

 

My comments were for the head with the heart-shaped combustion with no cylinder relief. Your first pic looks like a stock combustion chamber, which, in my opinion, can't be helped by milling. The statement that 7:1 changes a banger engine from a put-put to driveable is very accurate.

 

Short answer: The crack should be no problem. The head gasket with roughly .047/.050 space will make the "proper" squish distance for power. I'd run it. Just be sure to re-torque SEVERAL times!

 

Just a thought- I would probably break that sharp edge where the transfer area protrudes over the piston. Cool head!

 

something else you may want to double check is the thickness of the head after how much they milled it. bring it to a shop and get it sonic tested.

 

Thanks to all have replied! I appreciate you taking the time to help me out!

 

Thanks Jim! Is there a head gasket you would recommend for this application?

 

Thank you! I have heard the composite gasket can be hit-or-miss... hence the reason you see my pic with the copper gasket. You said the composite is the best you've found so far. Is this from personal experience? I'm not second guessing you, just asking.

 

Is there a gasket that you would recommend for this application?

Good idea!

Good idea!

 

I can't recommend a gasket brand but you are probably going to need one designed for a Model B engine not a Model A engine.

Charlie Stephens

 

Yes, personal experience and also assisting several friends in my MAFCA chapter.

 

Please tell me what your reasoning is for this recommendation, Charlie.

 

Look at the shape of the combustion chambers. The Model B heads had a combustion chamber generally called "heart shaped". It is best when the gasket matches the head. If you run a Model B block and a model A gasket there are also a couple of extra water holes that will be too close to the edge of the gasket with a Model A head and will leak if not plugged. These two extra holes will leak if you run a model B head (the one produced for the 1932 Ford) on a model A without plugging them.

Charlie Stephens

 

Highly recommend you buy the Jim Brierley book "4 bangers and more". You can cc head like this and his book has the math.

 

Thanks Charlie! This head will be installed on a Model A block. The "heart shaped" gasket makes very good sense.

 

Charlie, if you look closely you will see this might have a heart shape chamber but it is a Model A head not a B head. Best to stay with an A head gasket. I would be more concerned with how much was milled. Looks like they cut into the bottom of the water pump area pretty heavy.

 

I agree that it is a Model A head, probably part number A6050B. The heads usually carried a large cast block letter B on the top. The designation A6050B speed head may have been a post production or aftermarket head. These heads were originally released for the police departments. If you lay a Model A head gasket and then a Model B head gasket on the head you will see that the Model B gasket will more closely follow the combustion chamber and that is the reason I recommend it. Of course with the amount the head has been milled even the Model B gasket will not be an exact fit.

Charlie Stephens

 

Don't all the aftermarket Model A high compression head manufacturers recommend the B gasket?

Dave

 

Here is the info I found about the "SPEED HEAD" at this website
http://www.fordgarage.com/
Obviously, the cc and comp ratio have changed due to it being milled.