I Dont Know whats wrong with my 350 Chevy Engine?

Help.....i have a 350 chevy...when it is runing and in park it sounds really good...theres no missing no backfire no puttering....but as soon as i drop it down into gear it seems like the timing is Way off it doesnt even wanna stay runing...it has no power...i changed the timing chain %26quot;lined up the dots how i was supposed to 12 and 6 oclock...%26quot;i changed the module..the rotor button..the Ignition Capacitor and Harness..the wires..the plugs..carb is runing good.....i ran out of ideas...in order for it to even run good in park the distribitor has to be on about the 4 spot on the cap...and the Vac. advance have to be all the way advanced...when i take the distibitor out and put it in the 1 spot were it is spose to be...i have to have the Vac. Advance all the way retarted..or wat ever that way is called''it is turn all the way count clockwise%26quot; PLEASE CAN SOMEBODY HELP!!!! *i bought this motor of somebody they said it would run good after i changed the stuff i said but i did and nothing*I Dont Know whats wrong with my 350 Chevy Engine?
you need to check top dead center. take valve cover off turn the engine over with a ratchet and socket. watch the rocher for 1 intake when it closes then watch the timing mark when the timing mark lines up tha is top dead center. you may also check that thepiston is on top. remove 1 spark plug you can use a small screwdriver be carreful not to damage pistion. the distruber can go in in any position as longas your wires go to the right cyl.I Dont Know whats wrong with my 350 Chevy Engine?
Did you change the top gear? If not, it could have worn teeth which will make your timing be off.I Dont Know whats wrong with my 350 Chevy Engine?
How many miles are on the engine? 350's known to need complete rebuild after 100,000 miles. Mine went 125 K.I Dont Know whats wrong with my 350 Chevy Engine?
I had a similar problem in 1987 and it turned out to be that carb was messed up. I think that you may have the same problem. Basically when you put it into gear the air/fuel mixture may not be adequate to maintain an ideal idle. You've tried everything else so check it out, you don't have anything to lose!I Dont Know whats wrong with my 350 Chevy Engine?
Sounds like you need an expert like the ones at this site.I Dont Know whats wrong with my 350 Chevy Engine?
Could be the valves are set too tight. Warm up the engine. With the engine running, loosen the rocker studs one at a time until the rocker arm clatters. slowly tighten the bolt until it quits. Then give it another half a turn, one quarter turn at a time. There are gizmos that you can get that go on the end of the rocker arm that helps keep the oil from squirting all over the place. Its still kind of messy though. Could be a plugged exhaust.I Dont Know whats wrong with my 350 Chevy Engine?
Unhook the vacuum advance from the distributor. Set the timing at about 16-18 degrees advance at idle. Keep the vacuum advanced un-hooked (plug the hose with a golf tee). See what that does for you.I Dont Know whats wrong with my 350 Chevy Engine?
Well this is interesting. Unfortunately, we know even less about the engine than you do.

Since you know little about the condition and configuration of the engine/fuel system, you are trying to fix something without knowing what to fix. Is this a stock engine or was it modified ( as in camshaft ). Is it worn out? How much compression do you have? Is your ignition timing correct? Do you know what the timing is supposed to be? Some chevys have a timing mark(ignition) which aligns at near the 12 o'clock position while others align at the two o'clock position. Are the correct cover and balancer on your engine or are they a mismatched set? If your camshaft is a performance grind, it will act badly in drive at idle. Some people over cam their engines not realizing the problems it can cause.

Your troubles are not insurmountable, but it sounds like it is beyond your skill level. Any mechanic who works on engines and engine tune can straighten it out for you.