1985 Dodge Ramcharger erratic timing

new dist.,ecu modual,replace timing chain,battery charges fine,I rebuilt carburetor twice idles rough and plugs are sooty can't seem to adjust idle mixing screws started at 1 and one half turns to 3 turns rpm 's is erratic jumps 680 rpm's to 710 rpm's.The timing bounces from 12 degrees btdc to 10 degrees after top dead center, I have the pvc siting out side the engine block so the engine can breath idles ok , but when I put the pvc inplace the idle dies and loops could it be I need to replace the carburetor with a new one its a holley 2bbl. 2280 its not a lean burn type.The big thing is the carburetor giving me erratic timing,also ign. coil is new. can I do away with the ecu unit I read that you can just battery feed to coil to distr. and use the vacuume for advance.I was just thinking ,also new rebuilt engine thanks ,ron