[1972chevelle350]

Hello All...

I need some advice on HEI. I have a bone stock 350 4 barrel in a 72 Chevelle Malibu. I would like to convert to HEI, but don't know much about it. It seems that I could replace the distributor or not. Would it be better to? What are the advantages, other than getting to spend more. I figured that I would need to replace the distributor and internals, wires, plugs and such. Is this right?

I am living at 6000 feet, and everyone is saying that it will perform better. Can anyone tell me why? What is the difference? I think that it will just be providing an cleaner, hotter spark?

Thanks in advance...

-Matt

 

[anychevy]

I think that it will just be providing an cleaner, hotter spark?

Yes it will, but.
A true GM HEI (high energy ignition) uses a different (larger) distributor containing an electronic module instead of points.
The coil is located in the distributor cap and requires different leads and a larger .040 -.045 plug gap.
Here's some advice on points to HEI conversions
http://www.oldengine.org/unfaq/hei.htm
On a bone stock 72 low compression 350 it will make very little difference to performance or economy.
Also beware of cheap Chinese distributors, some are real junk and can do more harm than good.
If you just want to replace the points with an electronic device ? Look into one of these.
http://www.pertronix.com/prod/ig/ignitor/default.aspx
But the good thing about having points and a seperate coil is, just about anyone, anywhere can fix it.

 

[68KMENO]

yes you'll have to change the distributor & coil & wires ... & the power wire to it as an hei needs 12 volts ....... but one thing it will do for you is stay in tune for years !! as it has no points to wear out ... if your motor is basically healthy no oil fouling of the plugs.. tune ups on HEI cars are about as frequent as tire changes !!

use one of chevys stock HEI units you can buys parts for them anywhere if needed ...
also take extra care in routing the wires & using wire separators & stands to hold them in place ...... MOST HEI problems are caused by people not installing the wires correctly & them burring on the exh !!

 

[1972chevelle350]

Thanks so much for the info.

-Matt

 

[novaderrik]

you'll need to run a full 12 volts to the distributor- which is as easy as going to the closest junkyard and pulling the HEI power wire out of any GM car or truck with a rear mounted distributor that was made from 75-86 or so. get the whole wire- pull the bulkhead connector and use a small screwdriver to push the terminal out from the back- and replace the entire cloth covered resistor wire in your chevelle. if you take your time and put it in the stock loom, almost no one will know it didn't come in your car from the factory.
while you are pulling the wire out of the vehicle at the junkyard, grab the tach wire, too, since the HEI uses a special connector.