273 or 318?

[JTinAZ]

I’m trying to determine if I have a 273 or 318. There is too much grud on the block for me to get to the numbers right now but I was able to identify the stamping below the DS head. It’s 8490556. I can’t find anything with this number. Do I need to clean the block and find the casting numbers?

 

[toolmanmike]

I’m trying to determine if I have a 273 or 318. There is too much grud on the block for me to get to the numbers right now but I was able to identify the stamping below the DS head. It’s 8490556. I can’t find anything with this number. Do I need to clean the block and find the casting numbers?

Yes. Clean the block. That's a later model number so it has to be a 318.

 

[413]

Just look to the left on that stamping below the cylinder head and it will say the cubic inches.

 

[Dana67Dart]

What year do you think it is?



Front of engine, drivers side
C = 67 model year
273 = displacement
12-21 = December 21, 1966 engine build date

 

[Professor Fate]

Casting numbers (not stamped numbers) on driver's side of the block above & forward of the starter:

 

[JTinAZ]

If only my engine looked like that! Lol

I did find and R and 2 in front of the 8490556 after further inspection but still no cid stamp. Still no luck with that number either.

Between all the old oil and grud, the exhaust manifold, and the frame rail, I can’t see squat. I was hoping the stamped numbers would tell me what I needed without getting elbows deep with a wire brush and a pressure washer. Guess not!

 

[Dana67Dart]

Look for part numbers on the intake manifold

 

[JTinAZ]

So I used a scotch pad and revealed the full stamping. It is in fact a 273. The full number is PM273R 28490556.
I’ll have to clean the block up at some point to find a date code. I still suspect it’s not a 69 because it’s not red but I saw a low mileage original 69 recently with a 318 that was also turquoise so maybe they didn’t paint all the 273 and 318’s red in 69 as I had read.

 

[Dana67Dart]

PM 273

Is most likely BM 273. 66 model year.

Which is good, has modern intake bolt holes.

 

[JTinAZ]

Def a PM.

 

[Dana67Dart]

Well interesting.
? = 64 ( first year of 273)
A = 65
B = 66
C = 67
D = 68
E = 69 (last year for a 273)

Was P the last letter before they started over?

 

[Professor Fate]

Sorry if I sound like a jerk, but clean off the side of the friggin' block and read the casting date for crying out loud. Sometimes you need to get dirty in this hobby.
Passenger side:

 

[Dana67Dart]

Found a post that says:

PM = built at mound road plant
273
R = regular fuel
2849 - > 10k cal = Friday, May 16, 1969
0556 - Engine built

what yr is my 273??


Interestingly and maybe it started in 69, the stamping doesn't follow previous year codes

 

[JTinAZ]

Found a post that says:

PM = built at mound road plant
273
R = regular fuel
2849 - > 10k cal = Friday, May 16, 1969
0556 - Engine built

what yr is my 273??


Interestingly and maybe it started in 69, the stamping doesn't follow previous year codes

Thanks Dana67Dart! That confirms it’s the original engine.

Not afraid of getting dirty @Professor Fate, but the cars in a tight spot at the moment and it’s been 112 degrees all week. I was just trying to get some prelim info to make plans for the build after the summer heat.

 

[JDMopar]

Check on the passenger side of the block, on a machined pad just above the frame rail to see if it is your numbers matching engine. The machined pad is very close to the drain plug you can see on the side of the block. Last 6 numbers of your VIN will be stamped there if it's the numbers matching motor. You will have to jack it up and put jack stands under it to be able to do that. Too much work in that heat! Might have to wait for cooler weather....lol.

 

[JTinAZ]

Check on the passenger side of the block, on a machined pad just above the frame rail to see if it is your numbers matching engine. The machined pad is very close to the drain plug you can see on the side of the block. Last 6 numbers of your VIN will be stamped there if it's the numbers matching motor. You will have to jack it up and put jack stands under it to be able to do that. Too much work in that heat! Might have to wait for cooler weather....lol.

Yep, I’ve got the info I need for now. I can’t get under it right now and I can’t see anything from above, especially on the PS with the exhaust manifold.
The engine is siezed and the oil on the dip stick is dry sludge so my hopes of getting this running are low at this point even if I can free the engine up. I can only imagine what the internals look like.

 

[JDMopar]

From your prior posts, it did sound like it would be a while before you could do any more to it, and I don't blame you. The heat I worked in yesterday about did me in, and it was about 20 degrees less than what you're in! Just don't let the block get away if it does turn out to be the numbers matching one to your car. 273's generally cost more to build because pistons aren't off the shelf for HP type, but they can be had. The rest costs about the same.