Hot Rods Oldsmobile Rocket engine identification

Hi
I have an early oldsmobile rocket engine. I'm trying to find out what kind of rocker engine I have
( year, cu. inch..........) can somebody help me? Please see picture with the engine number.

Thanks for your answers

Patrick

 

55 heads had an 8 cast on them, 56 had a 10. That's all I know. Measure the bore and stroke-that will tell you for sure. @Paul will know, I bet.

 

A 555641 casting number block is a 303, made from 1949 till most likely 1953..most places say 1949-?

 

What is the stamped number on the deck surface outer edge between cylinders 5 and 7?

 

There will be a serial number stamped into the block on the side. A small flat area still visible when the head is on.
I have a list of those codes at home if you can give us the number and no one beats me too it.

 

Paul beat me to it.