IS the numbers for sm. blocks stamped somewhere on top of the engine like big blocks i'm going to look at a '70 340 from a cuda but i have only owned big blocks.thanks

There's a pad on the front of the engine, driver's side, right below the head. And numbers are cast into the side of the block as well.

Front of block drivers side, just below deck.

something like
FM340Pxxxx xxxx

VIN or SO number
68 along bellhousing rail, top side
69+ Pass side pan rail just below drain plug

ok so what numbers represent a '70 340 cuda engine. The engine is currently in a pickup truck so i'm real glad the nos. are on top. Thanks ,I'm not very knowledgeable on sm. blocks

what I posted should be on the front of a 70 engine.

The first digit "F" is the 1970 model year

D = 1968
E - 1969
F - 1970
G - 1971
H - 1972
J - 1973

Thanks Rob,thats what i need to know

"Mopar Engine Casting Numbers 1970.
The block casting numbers for all RB, B, and LA engines are found on the left (driver) side of the block. In addition, on 1968 and later engines the numbers stamped on the lower rail of the engines right (passenger) side match the last 8 digits of the cars vehicle identification number.
Casting Number CID Year Type Remarks
2780930 340 1968-73 LA Except T/A & AAR

Mopar Head Casting Numbers 1970.
The casting numbers for most RB, B, LA heads are found in two places. On the underside of the head on an intake runner, and under the valve cover on an intake runner.
Casting Number Engine CID Year Intake Exhaust
2531894 340 1968-70 2.02 1.6

Mopar Intake Manifold Casting Numbers 1970.
Casting Number Engine-bbl Year
3462848 340-4 1970

Mopar Exhaust Manifold Casting Numbers 1970
Engine Year Remarks Casting Number
340 1969-70 Barracuda / Right 2863549
340 1969-70 Barracuda / Left 3418623
340 1970 Challenger / Right 2863549
340 1970 Challenger / Left 3418623
340 1969-70 Dart / Right 2863549
340 1969-70 Dart / Left 3614368"

Here's a photo with one 1971 engine decoded as an example

Drivers front of block just below the head

The VIN sequence number is stamped here, just above the oil pan rail, passenger side, near the water jacket drain plug.

The top numbers you find will only tell you what engine, what engine plant & when the engine was assembled.
The partial VIN# off the side will tell you what plant the original car was built at.

If it is a '70 partial VIN# (0Bxxxxxx) Alaskan_TA, Barry, should be able to tell you if it was a 'Cuda, Challenger, or Duster.