How to tell matching numbers engine?

[Nomax]

I'm looking at a 70 Swinger, Fella sent a photo of the build sheet, Reads LM23HXXXX, Color on Build sheet says TX9, ( Car is plum purple ) He said its matching numbers, He did send a photo of the year on the side of the block 11-11-69, what would I have to look at to see if it is matching numbers?
Numbers on the block? to numbers on build sheet?

Thanks for the help fellas.

 

[72Swinger360]

1st off that date code makes it a 70 340 so that puts you in the right direction from the start.

The best way to tell if it is the numbers matching 340 is to look on the small machined pad on the RH side of the block just above the oil pan rail towards the front of the block. This pad contains a partial VIN number listed like 0B123456. Match this number to the vin of the car and you will know if it matches or not. The pad is almost directly below the date code on the RH side of the block.

I hope this helps,
Joe

 

[72Swinger360]

deleted

 

[Nomax]

Thanks Joe.!

 

[chasduster]

Joe is right....also on the car, on the left front top of the rad support their is also the vin stamped their....well on my 70 340 duster it is...