What Block is this?

[Iowamod20]

I have a SBC block that I thought was a standard 2-bolt 400. However, after cleaning it up, the boss where 509 is usually stamped is blank. The block appears to have a blue green factory paint on it.

These are the casting numbers I found:
T0822(0 or O)TC
14(S or 5)106763
The is a very big 030 stamped next to the casting numbers above.

The block bores do measure out bigger than 4.125, like it is a 0.030" over block. Did GM ever make a stock 30 over block?

Thanks.

[ka_jd7and1]

TC is the suffix code for a '60-'64 Chevy 348.

[dirty white boy]

TC is the suffix code for a '60-'64 Chevy 348.

348 is a truck motor,..chevys first big block,..its a W motor,..same family as a 409,..lotta boys stroke'ing the 348s an putting them in them impalias,.wish'in it was a 409....

[Iowamod20]

Thanks for the replys. The numbers I gave above are stamped on the deck, front passenger side.
As I said before, the boss where the 509, 511, & 817 is normally, is blank/smooth on this block.

I will look for casting numbers on the back of the motor, drivers side, and report back.

[Iowamod20]

The casting number on the back of the block, driver's side, behind head, is very hard to read. At first I thought it read 800817, but after looking thru typical SBC casting numbers, it may be 330817. Looks like it is a 70-80 block, and someone must of stamped the 030 on the deck after boring it out???

Thanks.

[racer69]

A blank boss means its very likely that it has been decked. Just something to remember.