Serial number location on Cat 30

There are three spots on my 30. On the left side of the engine block below the carb,rear of the transmission shifter cover there is a machined flat spot with serial numbers stamped in it, the third spot is above where the pto would attach at the rear of the machine. Hope thats of some help to you.

I've also seen them stamped on the block above the main clutch behind the last cylinder jug 😊

thanks guys , I found a number under the waterpump on the block S 1446 it is a cast number not stamped ,and 975 is stamped on the back of the rear housing just in front of the seat bracket (orchard model ) Can some one now tell me what year it was built ?

If it has PS in front of the number then it should be the serial no., my book said it would be 1927.

You better look again and look for a P in front of the S or another digit in the number. S1446 would be a 1922 Best30 and would make ie a 2 speed and worth about $20,000 more then your Cat30 LOL

Hello, s-1446 is the part number for the engine block, not a serial number.

thanks again all , caterpillarman : I thought that maybe it could be the part no for the block number also, not the serial no,thanks for pointing that out .--- Willie, Ive looked hard and there is no S or PS in front of the 975 stamped on the rear housing and it is a 3 speed with 2 sliding gear levers, so its not a Best, pity. My cat 10 also has the numbers only, no letters in front, so perhaps it's the same , I'll have to keep looking, you keep sending in ideas ,Andy

That no. stamped on back of block is supose to be date it came off the line but I have never figured it out. but the ser. no. will be stamped or on a tag not embossed in casting and unlike later machines the didnt stamp under the tags,look close on top of PTO housing for stamped no. or little tag behind the carb.