Conversion to HEI

• May 27, 2019

• #1

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magnum78

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Hello,

maybe anybody can help me. I have an 400 CUI in my Magnum 78.
After many Problems i removed now all the Lean Burn stuff and put an Edelbrock 600CFM on it.
Although i put in an HEI aftermarket (GM Style with Coil in Cap). Distributor in it.

Belive me or not, i need 22Degree initial Timing at IDLE (vaccuum unpluged) to keep it running.

Has anybody experience with an conversion to an "normal" distributor instead of the LeanBurn Stuff? (an Timing Chart for Intitial and TotalTiming would help).

Sorry for my bad english.

Regards from Germany

Manuel

 

• May 27, 2019

• #2

WileERobby

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First thing you'll need to do is determine true TDC of #1 cylinder, and where your timing Mark is at that point.

 

• May 27, 2019

• #3

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magnum78

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WileERobby said:

First thing you'll need to do is determine true TDC of #1 cylinder, and where your timing Mark is at that point.

Click to expand...

The TDC Mark 0 on the harmonic Ballancer is the true TDC. I double checked that with an blocking Plate while heads were off.

 

• May 27, 2019

• #4

Badvert65

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Back in the day, I converted many lean burn setups to just the basic Mopar electronic ignition. I never had an issue with the timing. They always ran fine at around 10* advanced (ball park-I would always start there). I wouldn't think the HEI conversion would be any different. Make certain the problem isn't something dumb like a vacuum leak or possibly some other lean condition. Check the EGR valve, to be certain it isn't leaking or stuck open. With the information given, I think the advanced timing itself is not the problem, it is just compensating for some other issue.
jus' sayin'

 

• May 27, 2019

• #5

Fran Blacker

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Here are 2 places to learn how. First is easier to follow. Second post #39 is a video he gets a little complicated because he runs a back up ignition, may not be a bad idea.
http://www.designed2drive.com/ https://www.forbbodiesonly.com/mopa...dule-i-already-hear-the-screams.156401/page-2

 

• May 27, 2019

• #6

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magnum78

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Hello, thanks, but the HEI ist not the Problem it think. I am concerned about the timing curve. Shop manual say to use emission sticker, and sticker say: