Your question illustrates EXACTLY why I get on my soapbox and rag people about calling the engines by their correct name.

What you call a "318" is either an LA 318 or a Poly 318 or a 5.2 Magnum. In this case I surmise the engine you want to replace is a 5.2Mag.

Likewise your "360" may be either an LA 360 or a 5.9 Mag.

Even though the engines have the same basic design and displacement (bore and stroke) there are enough differences to make correct nomenclature important.

Whether the 360 in question is a 5.9 Mag or a 360 from the LA line makes a lot of difference.

R.