390 timing chain
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Elder User
Joined: Jan 2012
Posts: 896
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From: AL
390 timing chain
I'm going to be changing the timing chain set on my 390. It is my understanding that Ford retarded the timing 4 degrees on this engine sometime in the mid seventies and before then the standard timing chain set the timing straight up. Is this correct?
I looked up a timing chain for a 1970 390 and the part number is different from a 1976 390. So to ensure I get the timing set "straight up" should I go and get a standard timing set for a 1970 390? I see some sets that offer adjustability but that just confused me.
I looked up a timing chain for a 1970 390 and the part number is different from a 1976 390. So to ensure I get the timing set "straight up" should I go and get a standard timing set for a 1970 390? I see some sets that offer adjustability but that just confused me.
Lead Driver
Joined: Jan 2003
Posts: 9,893
Likes: 12
From: Ohio
Get the 1970 model.
The typical factory replacement version has only ONE keyway. No adjustability. The aftermarket versions range from 3-9 different keyways in the crank gear. This is to enable you to adjust the camshaft timing slightly. Advancing the cam bring the power in sooner, retarding it moves it up the rpm scale slightly. To do this correctly you need a degree wheel and indicator to find the opening/closing points of the cam and work from there. In performance applications this is common practice.
For a stock replacement, putting it in "Straight up" is the way to do it(meaning no advance or retard). You may find that even the generic version you buy has 3 keyways. Just follow the instructions on which one to use. Usually they are marked with a triangle, rectangle and circle. One is straight up, the other are 4* adv and 4* retard.
The typical factory replacement version has only ONE keyway. No adjustability. The aftermarket versions range from 3-9 different keyways in the crank gear. This is to enable you to adjust the camshaft timing slightly. Advancing the cam bring the power in sooner, retarding it moves it up the rpm scale slightly. To do this correctly you need a degree wheel and indicator to find the opening/closing points of the cam and work from there. In performance applications this is common practice.
For a stock replacement, putting it in "Straight up" is the way to do it(meaning no advance or retard). You may find that even the generic version you buy has 3 keyways. Just follow the instructions on which one to use. Usually they are marked with a triangle, rectangle and circle. One is straight up, the other are 4* adv and 4* retard.
Hotshot
Joined: May 2003
Posts: 11,141
Likes: 25
From: south louisiana
If it were (the timing set) the keyway and the alignment dots would not be in line with each other. Ain't seen one yet that was like that, and I've taken apart a lot of engines with factory timing sets.
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