The RV8 slipped liner prob is generally accepted as being caused by overheating. This in turn tended to be caused by LR's requirement to run the engines lean in order to meet emissions regs...
Ive built a 4.6 from a spanking new block and do not expect any probs as it will be running cool, and be getting plenty of fuel.
If i was building from a 2nd hand unknown block i would have used top-hats.
Out of curiosity, what reason were you given for not using liners??? Ive heard nothing but good things about them...
Meant to add: There were 3 different thicknesses of blocks, marked by paint from LR. Red, Yellow, Blue (i think). The one you want is Red.