I'm not so good with the timing/distributor issues so I'd like to ask a few questions. First, the car is an 86 bird with a 67 327 converted to 69 accessories, electric fan, holley 600 vac sec, double hump heads, torker II, long tubes and glasspacks. Blah Blah, it was basically free. This is a parking lot queen, I haven't had it street legal in 5 years. Just a toy project. The motor has an HEI on it now and seems to act weird with the timing. Sometimes it's on, some it's not. Question 1. If the dist "goes bad" will the timing bounce around about three degrees in either direction at idle? Question 2. Is 8-10 degrees at idle a good starting point? no Advance timing light yet Question 3. If my dist is scrogged would it be a good idea to just get the $89 Summit one and have the adj vacuum and 50k coil, hi perf module, new cap and all instead of buying it separate and having to build it? Question 4. How crappy is the $49 one off of Ebay? Question 5. No backfiring is acceptable correct? Why would I be backfiring at 10* initial, 18* at aout 2500? thanks for all the help, this board is a wealth of info for the poorly informed(ME)

1-3: Yes.
4: Varies. Some, very. Others, no so much.
5: Need more details. 18 degrees @ 2500 isn't very much, though.

I don't think I could have answered any differently however a bouncing timing mark can also be a sloppy timing chain. Cam walk can also affect timing.

Distributors do not last forever. Years ago when I still ran an HEI, I searched the junkyards for weights and springs to get a custom curve. I found an HEI in a second gen firebird that was so worn out and the weights seized, I can only imagine the last owner being frustrated with how poorly the engine ran when all it needed was a new distributor.

I now use an MSD distributor.

I'll add to the above that the gear at the bottom of the distributor could be worn out and also contributing to jumpy timing.

that's why I love this board, all quickness with the answers. My cam /timing chain/mechanical parts are all in good working order. The motor has less than 100 miles on it, and I just inspected the timing chain when I pulled the cover to replace the seal. Anyone have a good link to a dist that's better/better deal than the summit one?
Anyone have a better suggestion for the timing to be than 18 at 2500? I'm unhooking the vacuum when I do that, should I leave it on?

If the advance mechanisim is working smoothly and the pins and weight haven't "eathen" into eachother I'd check to make sure the springs aren't too weak. You can end up with the centrifugal advance kicking in partially at idle. Then when you rev it up there's not much more advance left to kick in.

This can also cause an erratic idle timing reading as well. Something to consider.

Always check you timing with the vacuum advance disconnected, as you have been.

Unhook the vacuum line. If set up properly, the distributor should be at full mechanical advance by 3000 rpm. Depending on how much initial advance you set the distributor at and how many degrees the mechanical advance allows, your total advance should be between 32 and 38 degrees. How many degrees it's at between idle and 3000 rpm is part of the timing curve. A single point means nothing. It's like you having a 400 hp engine and saying it makes 250 hp at 3000 rpm. The best timing curve will be known by someone who recurves distributors. All you need to know is the initial and total timing and at what rpm the engine is at when it reaches total timing. The weights and center cam determine how much mechanical advance there will be. The springs determine how quickly the advance comes in. You can mix and match weights and springs for a custom application. One big weight, one small weight. One light spring, one heavy spring etc.

Any new replacement distributor will work fine. Even a local auto parts store replacement will do if yours is worn out. I ran a basically stock HEI in my car for years. I used an MSD ignition and an aftermarket coil but the rest of the distributor was factory stock.

Guessing at what's wrong will only be a guess. Since the distributor is a suspect, it should be taken out and stripped down for inspection.

thanks for all the replies, when I get my bonus check for the month we'll be gettin a new dist

While you're waiting for the check to come in, any idea what cam is under the Torker 2 intake?
If it is near stock that intake isn't going to work worth a damn.
Also, that short stroke motor is going to need tall gears in the rear end.
You don't have 2.73's right?

ha, yeah it's pretty much stock. only thing I have for now, this is a "temporary" motor. doesn't go to the strip, only for a little mean sound and decent driveability. A better planned more powerful mill is in the works for a couple years down the road. Nope I did have 2.73's but I cahnged it out for 3.43's. I can go back anytime, haven't really driven it yet with either...

so i have a gm hei distributor but it dont have a vac adv how would this work with a carb

i have a gm hei dis but it dont have a vac adv it has some 4 wires coming from it how would this properly work with a carb

The "small cap" HEI dizzies only work with an ECM to change the timing. There are a "few" large cap dizzies out there for Cadillac engines that don't have a vacuum advance, but they too need an ECM.
The only way to use a small cap unit without an ECM is in dragstrip applications where the timing will be "locked". They use a retard box to start the engine and then switch it to full advance after it starts.

well ths is a big cap