I know my base timing is 6 deg BTDC.

What is my total timing advance for my 1973 360 cu in eng?

My engine is bone stock with 170,000 miles on it. It is a 2 barrel carb with an automatic trans. No air cond.

 

initial + mechanical + vacuum = total...usually in the vicinity of 50 degrees

 

Congratulations on having a dial back timing light.

-Jared

 

I have a dial back timing light. On my Pontiac GTO with a 400;

34 - 36 deg BTDC is what the total advance is. With everything hooked up I check this at 3,500 rpm.

What are these Fords supposed to run at??

 

a guy i've talked to in the fe section about this said 36-38 but leaned more towards 36. I'm in the same boat as you at gettin my 390 timed right.

 

Should be about 34-38° depending on your particular engine. If you go any more it Will ping. This is with vac. adv. unhooked and plugged of course. Are you having trouble with timing or just curious? If you are just wondering and it runs fine then slap that timing light on there and see what it reads.

If this is all stock, your cam is retarded 4°. Thus the 6° initial. I would guess you are probably at 32-34° total mech adv.

 

Have any idea what initial timing would be on a 390 if the total was 36?

 

Should be 12-14°. I usually start by setting it at 10° and adjust as necessary from there. Straight up cam timing I assume?

 

From what I have learned on my 68 GTO engine builders is base timing is irrelevant. Set total advance timing at 3500 rpm and see if it pings. If it does back it down till it does not ping. For Pontiacs ideal is 36 if it does not ping. I have my GTO at 32 deg.

For my Ford I was wondering what is the ideal setting to start out at and then I can work back if I have too if it pings.

 

It's a stock 390 except intake carb and headers. So i guess it's straight up? I had it at 15degrees yesterday and it pinged after I started to give it gas off of a shift. It was light but noticeable. I believe it was a ping at least. I've had it set at 12 before and it pinged once. It's kinda irritating not being able to find a good spot lol

 

Well ideally you would get a new timing set to get your cam back to being straight up. 73 and later 360 cam timing is retarded 4°. If you have straight up cam timing then you would be looking for your sweet spot somewhere between 34-38° without pinging. You never want to go over 38°. With the retarded timing, I'd start at 32° and see where it goes from there.

 

The cam timing should be straight up on a 390, if you haven't touched the timing set. Sounds like you need to adjust the vacuum adv. Under load and partial throttle is where the vacuum advance comes in.

 

Well what would 32 be at initial? 8,9, 10? I ask because if you know then it's easier adjusting it rather than having someone rev the the engine and

 

And how do i do that, what is it that i am messing with? I have changed out the heavier spring the the distributor to a lighter one so the total comes sooner, that sound right for a truck goin the the mud?

 

That depends on the dist. curve. For instance: you have one dizz that has an 18° stop bushing and is set at 14° intitial. That makes 32° total mech.---Another dizz has a 21° stop bushing and is set at 11°. That also makes 32° total mech. adv.
I don't really mess with the stock distributors as much and this is mostly from dealing with MSD stuff so sorry if this doesn't help.
What I'm saying is it's relative to the curve of the dist. That's why you set total first, and work backwards as the OP has said. You give it the most total it can handle without going over 38° in this case, and then find the most initial it can take. Once you have those you can set the appropriate curve with springs and bushings.

So say yours doesn't like more than 36 total and 12 initial. Thats a 24° difference, so I would use the 25° stop bushing and set the initial back to 11° for a total of, you guessed it 36°. From there you play with spring combinations to get it in as fast as you can without pinging. Make sense?

Edit: we keep missing each other with the posts. I post before I read your last post lol. I'm not sure if the factory dist. has an adjustable screw or not for the vacuum adv. You may have to disassemble to adjust. If it does, like the aftermarket ones do, there should be a screw (allen wrench) at the hose nipple there you can turn to adjust the pressure on the diaphram.