EPF10k10 ram blocks

I'm not sure what a EPF10K10 block is but if you really are just talking about M10K blocks like you find in Cyclone V then you should be able to get two 256x4 memories to merge into a single block if you only need single port access to each. In x4 mode you have up to 2k words so if one memory used port A and the other used port B you should be able to dual port that memory and have up to 2kx4 available to each. Normally when I want to force this to happen I just write my HDL to dual port a memory and share it in the design. If you haven't already done so I would look at the embedded memory blocks chapter for the device you are targeting, it will describe what these memory blocks are capable of.