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Old 05-23-2016, 03:45 PM
Pyasher Pyasher is offline
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Default 1972 350 Distributor Wiring

is it possible for my engine to run if the plug wires are off - by this I mean #1 is where #8 goes - etc. I paid someone to replace the intake in 2014 and it has run ok - but I have time now so I decided to check to see if I could get it to run better. The idle is erratic and varies by about 150 RPM. I reset the timing from 0 to 10 Deg BTDC and noticed the wiring did not look correct. Also and recommendations on a good aftermarket replacement distributor - looking for reliability / hotter spark / better starting - it is going in my wagon and more power would be welcome but I do not want to add anything to the engine bay - new coil would be OK...

Here is the diagram I used...

https://www.google.com/search?q=1972...9m97fInv0yM%3A

Thanks
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Old 05-23-2016, 06:53 PM
carpoor carpoor is offline
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I always keep the stock distributor and convert the points to electronic ignition. Usually Petronix, Crane, etc. Works well, looks factory.
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1972 SS 454 Chevelle LS5/M21/12 bolt 3.73 posi
1969 Malibu factory L48/M20/12 bolt 3.31 posi
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Old 05-23-2016, 07:40 PM
Pyasher Pyasher is offline
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Quote:
Originally Posted by carpoor View Post
I always keep the stock distributor and convert the points to electronic ignition. Usually Petronix, Crane, etc. Works well, looks factory.
Thanks for the reply!

I have a Petronix in it now - works well but the distributor does have 100K on it. I for sure need to pull it and put it back in correctly... Still on the fence about a new distributor.
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Old 05-23-2016, 11:25 PM
carpoor carpoor is offline
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They really don't per se` "wear out." I prefer OEM parts over a lot of Chinese aftermarket junk. My guess is that it isn't phased properly. It might be a tooth or two off. Bring #1 to TDC, clock the rotor so that points to the #1 intake runner. I do all of mine like that, they start up and run well every time.
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1972 SS 454 Chevelle LS5/M21/12 bolt 3.73 posi
1969 Malibu factory L48/M20/12 bolt 3.31 posi
2001 Silverado RCSS LQ4/80E/4.11 posi. Cam'd & bolt ons
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Old 05-24-2016, 07:25 AM
Pyasher Pyasher is offline
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Quote:
Originally Posted by carpoor View Post
They really don't per se` "wear out." I prefer OEM parts over a lot of Chinese aftermarket junk. My guess is that it isn't phased properly. It might be a tooth or two off. Bring #1 to TDC, clock the rotor so that points to the #1 intake runner. I do all of mine like that, they start up and run well every time.
Thanks carpoor - in the past I have pulled the valve cover to determine TDC on #1 - is that the best way or is there an easier way?
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Old 05-24-2016, 07:51 AM
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Hank70SS Hank70SS is offline
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You can pull #1 plug and use a finger, thumb to feel the pressure build as #1 comes to TDC of the compression stroke. Then line up the timing marks to get to TDC.
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Old 05-24-2016, 08:04 AM
Pyasher Pyasher is offline
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Quote:
Originally Posted by Hank70SS View Post
You can pull #1 plug and use a finger, thumb to feel the pressure build as #1 comes to TDC of the compression stroke. Then line up the timing marks to get to TDC.
Thanks Hank - I could also use my borescope...
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Old 05-24-2016, 08:08 AM
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Hank70SS Hank70SS is offline
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Quote:
Originally Posted by Pyasher View Post
is it possible for my engine to run if the plug wires are off - by this I mean #1 is where #8 goes - etc..
Absolutely as long as the firing order is correct, 1 8 4 3 6 5 7 2. All depends on where the distributor was dropped in. Moving it 1 gear tooth will change the timing by ~28* if the everything else remains the same. Moving the wires 1 position will change the timing by 45* if everything else remains the same.

So you have to look at where the distributor is now. If you move the wires can you rotate the distributor 45* to get the timing right? Only have so much play because of the coil or power wires and the vacuum advance. If you move the distributor 1 gear can you rotate it 28* to get the timing right? If you do both then you only need to rotate it 17* to get you back to 10* advance.

Like carpoor I drop the distributor in with the rotor pointing towards #1 cylinder.
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Old 05-24-2016, 09:16 AM
Pyasher Pyasher is offline
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I did get the timing at 10* BTDC without moving the distributor. I will drive it this way until the winter when I have more time. Good excuse to pull the intake, repaint it and block the crossover so it does not fry the paint again. If you want it done right - do it yourself! Any opinion on new distributor vs keeping old one?
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Old 05-24-2016, 05:05 PM
mestorod70 mestorod70 is offline
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Ive always used an HEI distributor on any chevy engine i wanted power out of.
Upgraded with a better coil and a multiple spark type box.
A stock points type dizzy can be upgraded to electronic...and even use the points to
triger the aftermarket spark box.
That being said...i drill a few holes in my cap to aid air flow and reduce ionization that
WILL happen in hopped up ign systems
Im also a big fan of moroso blue max spiral wound plug wires....build em your self style
If you want the most performance and drivability....im assuming its a small block
Set your mechanical timing....NO VAC...to around 12 -14 initial and have total of 36 to
38 degrees all in by 2800 rpm
your vac advance should be hooked to a full time bellow the carb throtle plates port.
Your total timing with mech and vac advance should be limited to around 50 deg before
TDC.....Get the mechanical advance to make power first.....then modifiy the vac to keep the plugs clean while crusing.....if you get it dialed in...your fast and clean.
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