Sorry if a question like this has been asked a million times, but I'm kind of new to this.  On the card that came with my cam, there's a box that says "Adv. Timing", and lists 27 under BTC.  Does that mean I should be shooting for 27 degrees total timing, with the vac. advance hooked up?  

Those two values are not related in that way...

On the cam card is simply the point that the intake valve closes. Since the spark advance is degrees before top dead center on the compression stroke the cam timing should not DIRECTLY decide the ignition lead.

Spark advance is dependent on cam timing to some extent but it's also dependent on compression, combustion chamber shape, mixture motion, in-chamber turbulence, quench action, etcetera, etcetera.

If you're looking for a starting point for total spark advance give us some specs on your vehicle and I'm sure we can help you out.  

SBC 305 from a 76 Camaro, bored 0.040 over.  Stock heads, and the block was machined when it was rebuilt, so it may have a little more than the stock 8.5:1 compression. Edlebrock performer dual plane with a performer 500 cfm 4bbl.  Hooker long tube headers.  Cam is an older Wolverine WG-1103.

Any recommendations for timing?  

Oh - and the cam specs are 204/214 .420/.443  

Good combo you've got there,a performance curve has more inital timing and less in the distriburtor.For example 12-16 at crank and 20-24 in dist. for a total of around 36 all in by 2000 rpm or so depending on your application.Remember next time you post start up a fresh one.    WIEDER  

Took the advice of Weider in the last post, but I'm not sure I'm missing something, so let me ask what's probably another over-asked question.  I've set the initial timing to 13* for now, but I can't get the total timing over about 22*.

I've changed the weights and springs in the distributor with a Mr. Gasket kit, using the lightest springs in the set.

I'm using an Innova digital timing light, and the timing curve comes up nicely to about 2500 RPM, where I'm at 20* or so.  I get up to about 22* by 3000, but that's really as far as she goes.

I'm timing it with the vac advance hose disconnected at the carb, and the carb nipple capped.

From what I understand, I'm only picking up 7-9 degrees of mechanical advance, instead of the 20* or so Weider said I need.  Some folks have said just set the total timing by twisting the distributor and let the initial be wherever it falls.  If I do that and set the total for say 36*, then wouldn't that make my initial about 29* or so?  Won't that be too much for the starter?

Maybe I've just got a basic misunderstanding about timing.  If anyone feels like giving a "timing 101" class, I'd sure appreciate it.  

If I would have included vaccum advance!Most vaccum canisters give you about 10 degrees also,your there.Start over unplug vac. again set initial at 16,then check mechanical advance which needs to be at around 20 degrees  10vac + 20mech. + 16 int.=36 total at full throttle you will be about 36 total because the engine won't have any vaccum to speak of.Vac. canister gives advance from off idle and part throttle pretty much as engine speed increases mech.starts to take over and vac starts to decrease.    WIEDER  

You don't want that initial to be 29* or you will have trouble starting that engine,you don't say what kind of distributor you are using but it could be a case that the mech. advance has got some corrosion in it that is not allowing it to rotate to full advance.
 I have not used vac. advance for a long time but I think that when you are checking total timing that the vac. advance should be hooked back up,it should only be disconnected to set the initial and then reconnected,because if as weider says the vac. adds 10* you are missing that with it disconnected.
 One other thing and don't take this the wrong way,make sure you are using the timing light correctly,I was at the racetrack last year and a guy beside me had a Camaro that he was saying was way slower than what he thought it should be,he was setting the timing with a light that had more buttons and dials on it than the space shuttle and he seemed a little unsure about how to operate it,when we put my old standard light on it the advance was taking his total timing to almost 50*!when we reset the timing he made a pass and picked up almost a full second!  

Something is befuddling me here...

At 3000 rpm there should be enough throttle opening that the vacuum advance should not be functioning, shouldn't it? Also, I don't think in a mild case like this that all the advance needs to come in at 2500 RPM. 305's are known for pinging and bring in advance too quickly cannot help this.  

Good point GibTG,For a baseline I should of told you to start out with less initial like 12 and 24 or so mechanical.Maybe total timing in by 3000 would be better,I also should of said be prepared to invest some time to dial in unless you can afford a rear dyno tune.Push initial but like you said in your own post hard cranking can happen.Do you have bushings for your mech. advance to change the limit? Lean towards heavier advance weights and medium springs,lighter springs tend to stretch out with heavy weights.   WIEDER  

The advance kit I bought only had one set of weights and a center plate, and had two different nylon bushings, though only one of them fit the posts on the distributor (the others were too big and loose).  There were 3 spring sets to use; I used the lightest.  The weights in the kit looked smaller (lighter) than the ones that came with the distributor that I took off.

The distributor is new, but noting special.  Got it at a car show.  Its just a typical GM HEI with a Hypertech coil on it.  No MSD, no CD.

So, looking back over everyone's advice, I understand that:

1. Set the initial timing with the vac hose plugged, vac advance nipple capped and turning the distributor.

2.  Then, read the mechanical advance with the vacuum still disconnected and plugged, by increasing RPM.  Changing the springs brings the mech advance in sooner or later (lighter springs = sooner).  Changing the weights makes more degrees of mechanical advance (heavier weights = more advance?).

3.  Then, reconnect the vacuum hose, and increase RPM to read the total timing (intial+mechanical+vacuum) which should be around 32 in my case.

Finally, to pick up on invigerating's point about using the light correctly - I think I'm using it right.  Mine is the type where you point the light at the balancer and press the up or down arrow on the gun until the line on the balancer is at 0 on the timing tab, then you look at the LED screen and it tells you the degrees of advance and the RPM.  If it sounds like I'm missing something with that too, please chime in.

Thanks for all the help so far...  

The carb vac port needs to be capped is that what you mean not vac canister? Heavier weights will also make it come in sooner,more mech. advance is changed by the bushings or by grinding the correct sides of the plate where you can get a few more distributor degrees.You might have a adjustable vac canister which is for part throttle advance.At easy cruising you will have over 40 degrees total w/ vac canister until you push the pedal to the floor.Still shoot for around 36-38 total.As you have already noticed it can get really involved just to learn the basics of timing alone.  WIEDER  

I'd been pulling the hose off the carb, not the vac advance, and putting a cap on the carb nipple.  I was leaving the hose to the vac uncapped.