How to tell the difference between a 318 and 340

[David B]

I bought my 1970 Barracuda used. the fender tag said it came with a 318 but the air cleaner cover says 340 four barrel. How can I tell the difference? I'm having the engine pulled for overhaul so access to the block # should be easy.

 

[djais1801]

google is your friend:
Mopar Engine Casting Numbers

 

[340challconvert]

These may also help;
How to ID a Small Block Engine Block:

LA - Chrysler small block V8 engines

 

[gzig5]

How can I tell the difference?

A 340 generally pushes you further back into your seat than the 318......

 

[Hemivision]

It's cast into the right hand side of the block in my experience

 

[340challconvert]

David, look for a number on the driver's side of the block, front, right below the head. A 70 engine would start with F.
A 71 engine would start with G. The next letter is where the engine was assembled, followed by the cubic inches engine size.

Check out the link I posted above; it has actual pictures of number ID locations
"How to ID a small block engine block"

It will give you all the information you need with photo locations

 

[David B]

Thank y'all for your help.

 

[volunteer]

It's cast into the right hand side of the block in my experience

It's cast into the Left-hand side of the block - large numbers - basically behind the starter. You can read it with a good light and a mirror, as necessary. Either 273, 318, 340 or 360 will be displayed - then a dash (-) and single number.
ie: The 340 casting number will be 2780930-340-3.

 

[Hemivision]

It's cast into the Left-hand side of the block - large numbers - basically behind the starter. You can read it with a good light and a mirror, as necessary. Either 273, 318, 340 or 360 will be displayed - then a dash (-) and single number.
ie: The 340 casting number will be 2780930-340-3.

Sounds good to me.. just a slip...

 

[Edward Hackett]

I bought my 1970 Barracuda used. the fender tag said it came with a 318 but the air cleaner cover says 340 four barrel. How can I tell the difference? I'm having the engine pulled for overhaul so access to the block # should be easy.

 

[Edward Hackett]

My 1968 340.
All Mopar small blocks are similar.

 

[Edward Hackett]

The last two photos are the casting date, and even what shift cast it at the plant.