I have a 455 that was always thought to be pulled from a 70 w30 stick car under warranty. After looking at the numbers on the block recently I now believe it to be the warranty short block that never made it into 70 442. I was involved in the first teardown of this motor in'73 and it had the hi-compression forged pistons, 569 cam and a stick crank. the numbers on the block are stamped L70SB 3139 the 3139 is actually under the L70SB but I can't make my post look that way. I'm curious to find out how common this is.

 

Like this?

L70SB
3139

If this is what's on the pad where the VIN derivative goes, clearly this motor wasn't installed on the assembly line. By federal law, the block would have been stamped with the VIN derivative from the car it was installed in.

 

Yes Joe like that. I assume it means Lansing 1970 short block and the 3139 is the code for W30 4 speed.

 

Interesting, I have a block stamped very similar. L3E with 8401y underneath the L3E. Came in my '70 W30, info given to me was it was a marine or industrial?