Small Block Oiling System Mods

I've recently had a few oil pressure problems with a 360 and hydraulic roller lifters, the lifters themselves were nearly .001" smaller than normal hydraulics and when I checked the lifter bores with a dial indicator [dont have snap guages] there was .008" slop in the lifter bores. No wonder I have oil pressure problems, the block is at present at the machine shop getting the lifter bores bushed.
The funny thing is there was always reasonable pressure at the guage, the problem showed up in the rod bearings, luckily no damage done, just a dark mark on the bearing.