This may sound stupid, but I've never used a timing light... I've always tuned by ear.

At idle, turn the distributor one way and listen to what the engine does, then turn it the other way and you'll find that it does the same thing.

Starting clockwise, at some point, you will hear the rpm's start to raise as you turn the distributor. Keep turning it and then you'll start hearing pre-detonation as the engine starts to falter and the engine runs rougher. Now, turn he distributor counter clockwise and you'll hear the rpm's start to drop as the engine smooths out. Keep turning it and the rpm's will start to falter and the engine will start running rough and may even stahl.

Using your ear, see if you can find the sweet spot somewhere top middle of the two points where the engine falters. You'll know where it's at because the engine will just sing in perfect harmony. When you think you've got it, hook up your light and see where it's at... Then go take her for a spin and modify accordingly :-)

 

I suggested he start at 6 and see what happens, why is that "so much"? It's not. Neither is 8, if his engine will run with it without complaining (pinging). And yes, an engine will show better performance with more advance, provided it's not too much to cause pre-detonation. Again, his engine will tell him audibly where it's happiest. The factory setting on his engine retarded the timing purposely to raise the exhaust temperatures for emissions purposes. Also, running ignition timing more retarded makes an engine run hotter (not good for performance). It's no secret that engines from this era were dogs, and the non-performance minded ignition settings were a contributing factor. And on top of all this, his engine is no longer "factory", so (suggested) factory settings go right out the window anyway.

 

so start at 6 at idle with the vacuum unplugged from the dizzy and plugged going to the carb?

 

Right. But if the idle doesn't speed up at all when you disconnect the vac hose, you don't need to plug it.

 

I was not refering to your post but his post about starting at 10-14. I agree with you about the start here and move up as needed. Too much advance will hurt performance just as much as not enough. Also he added a new cam but did not readjust the carb to the new cam. This will create a lean mix which could also be helping cause the issue with the red hot headers. I am just saying that he needs to look at the whole picture and not try to over advance his timing.

Massey

 

Oh ok, I was wondering why you thought 6 was high. As Gilda Radner used to say, nevermind!

 

My dad built an engine once that was a sweet performer... kinda. It had all the goodies on it like aluminum heads, 272 cam, roller rockers... you get the idea. His son (me) by this time had some schooling on building engines and was offering some advise on how to get it to run better. Dad would not listen to me... a buddy at his work on the other hand was telling him to set the timing on 12* and the engine was falling on its face from too much air so why would you put a 750 where a 600 was... and so on for a few things. Long story short, Dad asked me to change some plugs and give the truck an oil change. OK so I did, and I reset his timing and put my 750 Edelbrock in place of his 600 Edelbrock. I didnt tell him what I did but boy would that truck move after that. I got everything tuned good, it would not fall on its face when you punched it any more and it would squawk hard into 3rd, and start easy. Dad liked how it ran but was pissed that I put my carb on his engine. (my 289 could not handle the 750). He made me swap carbs back and I did, and once again the engine fell on its face when you punched it. He would not admit that I was right and that his buddy didnt know what he was talking about. I left the timing alone and that helped the engine run good. He brought the truck to a dyno shop and they told him he needed a 750 carb (I had sold mine by this time) and after he puts one on the engine they would tune it. I missed perfect static timing by 1* and they played with the metering and fly weights a little to dial the truck in good. After that no more on its face and it would squawk 3rd again.

Massey

 

Factory timing marks are useless with a new cam. They will throw everything off if you try to time using the stock marks. You need to either do it by the brail method, or use a degree wheel to set the timing.
If you retard the timing until it begins to start easy, but not run on when the key is turned off, that's a good place to begin. Then just tweak it a few degrees advanced and run it around. If it begins to ping, or gets where it wont start easy, then retard it a few degrees.

 

i was thinking that when installed the dizzy i had the rotor pointing to the #1 cylinder and the timing pointer was at 12 btdc, but i didn't have the #1 terminal in ine with the rotor!! does this matter? i hope not.

 

You must have been close enough, or the engine wouldn't have started. All those line-up reference points are for getting the engine initially started. Once the engine is running, those references mean nothing; the only thing that matters is what the timing light tells you. There's no such thing as the distributor being "off a tooth" if the engine is running. But it would be out of time, which is what you're adjusting.