@ram250098, It's difficult to diagnose engine noises over the internet since what you describe as a knock could be a number of things from detonation, bearings, insufficient oil pressure, piston slap, etc. Changing sparkplugs won't inpact lifter noise. The A313 is an under-bored A318 used in export vehicles, so the only differences from in the 1957 - 1961 313 and 318 are the pistons and camshafts. 1957 - 1961 A313 or A318 crankshafts have the same 3.31" stroke and will physically bolt into either block, but note that using 313 pistons with a 318 crank or 318 pistons with a 313 crank requires balancing the rotating assembly since the piston weight differs by more than 2 grams.

If your desire is to install an aluminum TorqueFlite 727 (or 904) and dig into the engine to overhaul or rebuild it, my recommendation is to find a 1962 - 1967 A313 or A318 and swap it in since 1962 onward 727/904 transmissions and torque converters bolt up. If you cannot locate new overbore 313 pistons, your machinist can bore the block to the 318's 3.91" bore where you can use standard A318 pistons. You'd need to have a new driveshaft built and address the transmission crossmember. Otherwise, if you wish to stick with the pre-1962 engine, you're limited to the iron PowerFlite and TorqueFlite transmissions, or you can purchase an adapter to mate a 1962 onward aluminum TorqueFlite to the early block, but they are expensive. I have a bunch of info on the poly A-block engine, parts interchange, and transmission options on my website that might help.