Fastang,
Are you using a PCV setup or just open breathers? When I first built my 347 I had 2 K&N open breathers and would blow oil out like you would not believe. My engine generated enough crankcase pressure to blow the RTV seal at the back of the intake manifold. I switched to a PCV & breather setup and no longer have the problem. Could the oil burning could be causing your computer to get wierd readings and hunt for an idle? Can your computer handle all the fuel changes? One of my buddies had a very similar problem on his vette with it constantly searching for the proper idle map. He had a new chip burnt and it fixed the problem.
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347 (Coast High short block), 279/284, TFS TW heads, Stealth, 750 Holley, Flowtech hdrs, Dr. Gas X, 2 Chmbr Flowmaster, MSD 6AL-Dist.& SS coil, March serpentine pulley system, Art Carr C-4 (Soon to be a Richmond 6 spd), Currie 9" w/3.50, alum Drv Shft, susp mods, Total Control subframes & tower braces, Trans Am Racing power dual master, 4 wheel disc, 17x8 Torqthrust II's
Something up my sleeve
In a 66 coupe