Reading a Engine Seriel Number

[Pjd1929]

Hello - I am new to this post - I need some help decoding what the seriel number on the side of my 1972 Chevy c20 engine means. I beleive I have an original 400 - But I am afraid I have something else.

The code on the side of the engine is
Gm 1rh 353030 n

I aM THINKING THE 353030 should be included in the seriel number some where - and they are not ?!

Any help woudl be appreciated thanks

[67c10rustbuket]

Welcome to the forum. The only thing I can find on that number is an exhaust manifold from a 454. Where exactly on the engine did that come from? Check on the front passenger side of the block where the head bolts to the block, there should be a flat machined surface there with a suffix code and partial vin, also on the rear driverside there is a casting number behind the cylinder head. Here are a couple pics of what you are looking for.