Timing is Too Advanced

I just got my Trans Am, with a 77 400 ci motor, started and it sound like the timing is fairly close; however, when I put a timing light on it; the light flashes 30 deg. BTDC (more or less). As I move the distributor the engine starts to die at about 18 deg BTDC.  

Before I started the engine for the first time I moved #1 cylinder to TDC and positioned the rotor pretty close to the # 1 wire.
Weaver Automotive built the engine so I will assume it was put together right.   Does anyone have any ideas about why the timing light comes on so far ahead of the timing marks?  

Did you unplug the vacuum advance hose from the distributor?  
A little help... 'cause we don't all have to learn the hard way!

No, the vacuum was attached I will remove it and try it again in the morning. Thanks  

I removed the vacuum and got it timed to 18 deg BTDC (the motor likes this over the 16 deg. that the book suggests) but one cylinder makes a loud pop like it is firing with the exhaust valve open - Sometimes but not always.

I did not build the engine and in fact it has been lots of years since I did build one. The car was a basket case when I got it so I can't tell you if it has the stock cam.

Could mixture cause the "pop" or should I be looking elsewhere?  

examine the spark plug wires....   ohm them...   set meter to 200K OHMs... each wire should display less than its length in inchs on the meter at this setting..      24 inch wire should be less than 24 on the display...     when the wires don't get pushed down into the cap tight.. or the spark plug connectors have been pulled off the end of the wire...

it could also be carbon tracking inside the cap and on the top of the cap...  i have seen it in both places..

a compression test is also needed...  to make sure that you don't have a burned valve or seat...

you could also have a valve guide going bad...  and when the valve closes off center.. it will let the combustion pressure past the valve seat...

i have also seen once in a great while..   thin wall valve guides slip in ... it will show up with a low compression reading on that cylinder usually..

have you pulled the valve covers and cranked the motor with the ignition disabled and watched the rocker arms... make sure they all move the same amount..   do this with the spark plugs out...  easier on the starter...

if you see a push rod that is turning really fast.. or back and forth... you may have found a flat cam...  

Thanks for the advise - it looks like one lifter was hanging - probalby from sitting a long time.  I've got it working now.