Timing
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Joined: Jul 2001
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Timing
Can anyone tell me what the total timing should be for the 390, Initial, Vacuum, and mechanical? I would like to know what the initial is how much vacuum adds and total with mechanical advance. Any help would be appreciated.
Thanks
Thanks
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Post Fiend
Joined: Dec 2003
Posts: 6,658
Likes: 4
From: "Islander"
timing
Depends on your compression and grade of fuel your running plus auto or stick.
With a 410 auto with spring kit the initial is at 12* centrifigual begins at 650 rpm's and full at 2,250. Total with centrifigual and vacuum is 37*. With the wide slot in the dizzy the post has a thin tube to shorten the centrifigual amount. I have the old style vacuum advance units that can be adjusted in amount of advance total and in how many inches vacuum. Every motor is different so tune for it and not the "general book specs". Hope this helps.
Carl....=o&o>....
With a 410 auto with spring kit the initial is at 12* centrifigual begins at 650 rpm's and full at 2,250. Total with centrifigual and vacuum is 37*. With the wide slot in the dizzy the post has a thin tube to shorten the centrifigual amount. I have the old style vacuum advance units that can be adjusted in amount of advance total and in how many inches vacuum. Every motor is different so tune for it and not the "general book specs". Hope this helps.
Carl....=o&o>....
Laughing Gas
Joined: Jul 1999
Posts: 1,048
Likes: 22
From: Lacey, WA
Hi,
There are just too many varables to answer your question correctly.
If your 390 was like mine use to be then stock it would have had about 6* initial and a possable 38* mechanical if you rev'd it hi enough. Like past 5500rpm. Not sure how much vacuum adds.
I recurved my distributor and now run 12* initial and 26* mechanical all in by 3000rpm.
Computing your timing is easy if you have a timing light, especially one with the delay **** on it. If you take apart the distributor till you can see the reluctor you can read directly off of the reluctor what your total mechanical is. You will see a different number stamped on each end like 13L and 18L. This is what mine has. Only one end is used and it is the end that bumps up against a stop post. Just take the 13L number and multiply it by 2. That's your mechanical. 26*. Add this to what ever you set your initial to.
Take care,
Lee
There are just too many varables to answer your question correctly.
If your 390 was like mine use to be then stock it would have had about 6* initial and a possable 38* mechanical if you rev'd it hi enough. Like past 5500rpm. Not sure how much vacuum adds.
I recurved my distributor and now run 12* initial and 26* mechanical all in by 3000rpm.
Computing your timing is easy if you have a timing light, especially one with the delay **** on it. If you take apart the distributor till you can see the reluctor you can read directly off of the reluctor what your total mechanical is. You will see a different number stamped on each end like 13L and 18L. This is what mine has. Only one end is used and it is the end that bumps up against a stop post. Just take the 13L number and multiply it by 2. That's your mechanical. 26*. Add this to what ever you set your initial to.
Take care,
Lee
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 423
From: Long Island USA
If it's totally stock (which it ain't if you have a 390 in a highboy), I can look it up in a Motor's Manual I have.
If you know what year it came out of, tell me. Other than that, give me the dizzy number and I'll see if I can find it in the book. Only from '67 through '79 though (FE's stopped in '77.5(?)) That won't tell you what it "should" be, just what it currently is.
art k.
If you know what year it came out of, tell me. Other than that, give me the dizzy number and I'll see if I can find it in the book. Only from '67 through '79 though (FE's stopped in '77.5(?)) That won't tell you what it "should" be, just what it currently is.
art k.
