engine numbers

[camelot]

Does anyone have a matching numbers 1940 Lasalle? I'm getting confusing info on exactly where the numbers are supposed to be. Some say back of block on flat area of block where bell housing bolts to and some say front of block on passenger side next to head. My number matches frame and is on back of block. But I thought the only difference between lasalle and the larger Caddy was the under bore?  Seems my block does not have the flat area on the passenger side.  I know 39 was supposed to be the last year for the rear ID number stamp. Couldsomeone set me straight on this? Thanks in ADV.

[Bob Schuman]

Alex,
The Cadillac and LaSalle V-8 through 1941 had the engine number on the back of the block, behind the driver side head, stamped parallel to the dash, as you have found. Since your number matches the chassis number on the frame, your engine is the original one in that car. Starting in 1942 the engine number was stamped on a pad at the front of the right side block behind the water pump.
There were three differences between Cadillac and LaSalle engines of that vintage. One, the LaSalle cylinder bore was 1/8 inch smaller than Cadillac, so pistons were lighter, offset by piston pins that were heavier by having a smaller hole lengthwise in the pin. Two, the LaSalle did not use a harmonic balancer on the front of the crankshaft, just a plain pulley. Three, LaSalle did not use the flexible flywheel that Cadillac used, intended to smooth the clutch action.
The LaSalle 322 engine can be safely bored 1/8 inch to use Cadillac pistons, as was done on my 1940 LaSalle engine some years and many miles ago.

Bob Schuman, CLC#254

[camelot]

Confusion Cleared! Thank you Bob. I just bought another engine and the numbers didn't add up. The engine that is for my 39 turned out to be a 41 346 from a 62 series. Number was on the back. 83xxxxx. The engine in my 39 presently turned out to be a 46 84xxxxx.  Guess I'm straight now. Thanks again.