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Discussion Starter #1
Hello Mustang Gods,
I need a little help. My dad and I built a 65 when I was 16, over 25 years ago... We built the engine from a long block we bough from PAW. I need help in the easiest way to identify the heads that I have on it and the pistons that are in it. I have the engine on an engine stand ready to go in 66 but I need to know a couple of specs, like combustion chamber size, so that I can get the appropriate parts and plan upgrades. The heads have no casting marks on them at all.

I really don't want to take the intake and heads off, but if I have to I will.

Thanks in advance for any help you folks might provide.

Also, I will start a built thread soon on this guy. It will start simple then go a little more wild as my kids get older and they are more interested and can help more.
 

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If you remove the oil pan there maybe marking on the pistons from underneath. For the heads without any marking or identification not sure anyone will be able to guess at all what you have, aluminum or iron? Unfortunately for heads without marking I think you will have to remove them to measure the CC and measure the valve sizes.
 

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Time for a teardown. You might find a head id under the intake manifold. And you'll want to pull at least one piston to verify ID and possible overbore (sometimes overbore isn't stamped on the piston head).
 

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DatB, the 1965 heads have a 54 cc chamber. Can you look through the plug hole and see if the pistons are flattoped or dished ? What is it about the engine you want to know ? LSG
 

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Remove the valve covers. In the top of the heads, between the valve springs somewhere, you will find 289, 302 or 351 cast into the head. Then look for a casting date code which will consist of 2 or 3 numerals and a letter, something like 6A5 or 8M13. The first code decodes to 1966 or 1976, Jan, 5th. The second code decodes to 1968 or 1978, Dec, 13th. With those numbers we can probably determine which heads you have. The positive identifier is found on the underside of the intake ports and you have to remove the manifold and use a mirror to see it.
 

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Unfortunately, the only way to find the casting number on the heads is to remove the intake and look at the underside with a mirror or to remove the heads entirely. The pistons you may be able to ID with a borescope through the spark plug hole... cheap borescopes that you can plug into your smartphone run about $10 on eBay. Even then, you might not be lucky enough to have a piston with the part number stamped on the face.... maybe nothing at all or maybe the oversize... if so, you can only guess at it from the presence of valve reliefs and even then you won't be able to verify the compression height.
 

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Discussion Starter #7
Thanks guys for the replies. The heads are after market (I think) as we got them as a part of the long block from performance automotive warehouse.

I think I'll pull a head but I might try the bore scope first.

Thanks again.
 
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