OIL pump pick up,and engine rebuild.Q M30 E28/E34

[BM WORLD 1258]

My Webpage stuff etc etc http://www.cardomain.com/id/greyhartge

I'm going to overhaul a 3.5L m30 218HP (10:1comp) engine in my M535i ,its done 462000km ,the front 2 lobes onnthe camshaft are worn down (lack of oil been feed to them ) the spray rail oil holes were back fromthe lobes . also the oil light stays on for about 10-20seconds after starting . the engine runs ok except for the top end noise from the number one rockers.also when the engine is warm and back at idle the oil light flickers sometimes( the oil in the engine at the moment is pretty black and gritty been sitting for 8months and the service lights are all on ) .so i was planing to remove head to get the camshaft rebuilt and reground up.but also i should look at doing valve grind /seals etc .i dont know whats been done to the engine as far as servicing , i thought while i have the head off i might do the rings as well and should i look at doing the oil pump as well ,I have a spare E34 535i 211hp (9:1comp) enigine sitting there which is for sale ,but i was thinking about weather i should keep it for parts ,maybe use the E34 head , can i use the internals from the oil pump from a e34 into e28 oil pump ,i know the sumps and oil pumps are different . should i use the E34 lower block (only done 211000km)and put the E28 pistons into it with new rings etc .

any info or help would be appreciated