Beginner Question: How to tell 273LA from 318?

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Grumpy Pete

Grumpy Pete

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Admittedly, I am relatively new to mopar restoration. I purchased a 65' barracuda about two months ago under the pretenses that this was the original 273 but am starting to think I have been bamboozled!

That being said, I am not sure how to tell if it has been swapped without pulling it out. Anyone able to help? I can get your any additional information you might need but lets start with couple images.


image2.jpeg
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Look on the block just below the head for a letter and numbers as well locate the casting number on the side of the block. Let us know what you find.

The air cleaner is from a later car!
 
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Driver side of block.
7D220856-2E8B-4860-B7E0-BA0D67349706.jpeg
Thats where i found numbers on my block. Pretty clear what mine is....
 
hi, I looked at my 3 273 blocks, one has 273 cast on drivers side. the other blocks do not. on the left front of block, below the head is stamped R 273, all my blocks have that. also, I notice you have a high rise intake, 273 intakes were flat.
 
Chime in if anyone has seen different but I don't think I have seen a 318 block that didn't have the 318 cast into it.
 
Also, about that intake, the angle of the bolts attaching to the heads, shouldn't it be not this? Or is 65 already the newer angle?
 
Max1196 said:
Also, about that intake, the angle of the bolts attaching to the heads, shouldn't it be not this? Or is 65 already the newer angle?
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Very observant. I finally got off my phone and onto a larger screen. It looks like the bolt heads are at a right angle to the head surface. If that is the case, it has a non-original engine, a 66 or newer 273or a 318. A good engine whichever one you have.
 
should the intake be a single plane not the duel intake shown?
 
Yes, if it was a Commando to start with it should be a single plane 4 barrell. Those came out in 65.
 
64, and 65 273's, intake bolts are 5 /16 inch and will take a 1/2 inch wrench/socket to remove/tighten; intakes are single plane, both 2 and 4 bbl; 66 and later 273's intake bolts are 3/8 inch and will take 9/16 inch wrench/socket to remove/tighten, intakes are still single plane, 2 and 4 bbl.

a big inspection mirror on a stick would help to read casting number on block.
 
Grumpy Pete said:
Admittedly, I am relatively new to mopar restoration. I purchased a 65' barracuda about two months ago under the pretenses that this was the original 273 but am starting to think I have been bamboozled!

That being said, I am not sure how to tell if it has been swapped without pulling it out. Anyone able to help? I can get your any additional information you might need but lets start with couple images.


View attachment 1715114513 View attachment 1715114514
Click to expand...

Here's a thread on how to ID a small block...

How to ID a Small Block Engine Block:
 
JBurch said:
64, and 65 273's, intake bolts are 5 /16 inch and will take a 1/2 inch wrench/socket to remove/tighten; intakes are single plane, both 2 and 4 bbl; 66 and later 273's intake bolts are 3/8 inch and will take 9/16 inch wrench/socket to remove/tighten, intakes are still single plane, 2 and 4 bbl.

a big inspection mirror on a stick would help to read casting number on block.
Click to expand...

Bingo. Until the op id's the block it is pure speculation as to what it is.
 
On my 1965 Dart, which is supposed to have a 273 cu in, the block has 2465330-4 stamped on it. I looked at the "How to ID a Small Block" post, but my stamping doesn't seem to add up. I don't see "273" in the stamping.

Can anyone decipher the 2465330-4 engine code?
 
Google is your friend... the first result (Enginelabs) shows your number to be a 64-66 LA 273. So you are good...
 
The OP's engine could still have the original block and later heads and intake on it. Very common thing to happen as the original 315 heads were crack prone and intake choices were rather limited. Casting numbers and stampings will tell the tale here.
 
JBurch said:
64, and 65 273's, intake bolts are 5 /16 inch and will take a 1/2 inch wrench/socket to remove/tighten; intakes are single plane, both 2 and 4 bbl; 66 and later 273's intake bolts are 3/8 inch and will take 9/16 inch wrench/socket to remove/tighten, intakes are still single plane, 2 and 4 bbl.

a big inspection mirror on a stick would help to read casting number on block.
Click to expand...
Juz sayin but that only tells you what HEADS (and maybe intake) are on the short block. To show you how far astray you can be, in the early 70's I "dumped" a good set of 273 heads/ intake on a THREE SIXTY short block. It was a torque monster up to about 4K RPM and then you might as well shift---or turn off the key, because it didn't get any better LOLOL
 
toolmanmike said:
Chime in if anyone has seen different but I don't think I have seen a 318 block that didn't have the 318 cast into it.
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I have not. Every 318 I have ever seen, including the 66 and prior had "318" cast into the side of the block.
 
toolmanmike said:
Very observant. I finally got off my phone and onto a larger screen. It looks like the bolt heads are at a right angle to the head surface. If that is the case, it has a non-original engine, a 66 or newer 273or a 318. A good engine whichever one you have.
Click to expand...
Not to split hairs or argue, but the later small blocks did not have right angle bolt holes to the intake face. They are closer than the earlier 273s, but not at 90*. I thought they were too, but there was a thread on here......I think it had to do with that intake jig they were shipping around for guys to drill their heads to the Magnum pattern that that was discovered.
 
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