318 hydraulic lifter preload.

Where do you read the engine has already run?

Lifter preload would be 'best' if the lifterplunger is about halfway its travel, with the lifter on the base of the lobe.

If lifter preload is not sufficient, you could install thinner headgaskets and/or mill the heads a bit more.

Stock engines came with steelshim headgaskets and during 99% of the rebuilds, thicker composite headgaskets are installed, lowering compression ratio.