engine timeing help

I have a 95' chevy heavy 3/4 ton silverodo, I had just re-built the 350 engine, added- new cran cam {computer friendly), 0.030 over flat-top pistons, better then stock valves, springs, and roller rockers. I also
installed a MSD ignition box (6A) and blaster coil, but has stock distributor. I cant get the engine to run right at all!
I tryed advanced, i tryed retarding... but no better, I am disconecting the timeing wire when im timeing it and doing everything right but this thing just dont want to run right! any help would be usefull
I also get read code 42 off the computer, code 42- electronic spark control ... PCM/ECM has seen an open or grounded EST or bypassed circuit is this maybe caused by the MSD ignition box? or could this be where my problem is?
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don't get pissed but, have you checked that your plug wires are on the distributor correctly?
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yes dave i did check that. See my engine is acting like the ingnition is retarded to much, the back-fire thru the exhaust.. But when i try to advance the timeing it dont want to run very well at all. I removed my spark plugs and they seem to be fine, light tan, but a little black around the bottom of threads but not the electrode itself, I had my heads off earlyer and all seems well inside also, i checked that all plugs were fireing, and they were. I re-gaped my plugs a little bigger 060 and it semed to make a little difference but it still is retarded to the pount of back-fireing off idle (if I rev it up, when it comes back down to idle- it lets out some nice pops) I was thinking maybe the O2 sensor but I checked that out also and found nothing wrong there.
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Are you sure the cam timing matches the crankshaft timing. A cam off time may let an engine run, but usually rather poorly, often requiring excessive advance or occassionally retard in the spark timing.
dingo69 wrote:

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Pull your timming chian cover and I thoink you will find you are off one tooth on the cam. Easy to do. Have done it my self. Good luck
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