Thread: Need help converting to HEI.

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I've got a '72 SB 350 in my '58 Chevy pickup. What is involved in switching to a GM HEI distributor as far as wiring? Is the coil integral in an HEI system? How is it wired into my truck with my current system? Is there just a single wire? Would I continue to use the factory ignition resister when I hook up an HEI?

Sorry, I know that's a lot of questions. I've been considering making the switch (space permitting) and when it comes to electricity, I'm in the dark (pun intended).

I don't want to go Pertronix as it doesn't seem to be a true high-energy electronic system. Rather it's just a replacement for the points, I believe?

As always, any help is appreciated.

going to hei is easy , you dont need your resistor . all you need is room for the dist itself and full 12 vlt power to the distibutor. there is a tach connection also right on the dist to run the tach off.

oh yeah the coil and everything is in the dist you will need new wires too as the hei has different ends on it.

Thanks! I appreciate the help! It's so nice to be able to come here and have all my questions answered.

My 73 Z-28 easily converted with no problems. Definitely do it.

one small detail for ya. The HEI distributor needs at least 12 GA wire. One way to accomodate this, is route the points wire to a relay, and have the relay switch a 12 GA wire feeding the HEI. You can take the switched wire straight from the battery, but it would be a much better idea to add an inline fuse ( 20 A ).

I have a question on this guys and not trying to take over the thread either. But while we are on the subject.... I just got my MSD upgrade HEI kit today, they Tune Up one. Anyways the Module will not hook up. On one side of the module you have the wires that hook up the the cap and coil, that all is fine but the other side has two prongs. This is my problem, my old one had THREE prongs not two and so the wires going into the dissy to those prongs have the female piece with 3 small prongs and the 2 big prongs on the module wont go into it....
Any idea why this is and how to fix it? I need to have this problem solved by tomarrow
Oh also the MSD kit is nice because the one I got has a rev limiter on it which they just started doing the guy said because he said they used to not have them in this kit.
Thanks a lot for any help and yeah upgrading to HEI is nice!

fmx, sounds like to me you have the wrong module for your dist. there are all kinds of modules for the hei dist. 4 pin, 5 pin, and 7 pin that i know of.

FMX,in answer to your question,I believe the module you need
is the 7 pin. 'Cause GM had a limiter after a fashion w/ their
brain boxes in factory vehicles. Old Gold, in case you wondered
the Mallory coil(s) are good for the HEI. Same same, Pertronix,
even Proform which is low buck (but Gary at American Speed in
Colorado Springs,CO will use a Proform in his drag car)I named
the above 'cause their output is higher than say Accel or even
MSD coils. Like modules same same, have heard good things
about Pertonix modules. Like, MSD's module replacement,also,but
is overkill unless you'll spin to 9,000 grand.Also Mallory coils are
purpose built 1 for up to idle to 5,500r's,e.t.c.And all above fit in the stock location for HEI coils. Hope this helps.

Man... Well when they say 4 pin or 7 does that mean the 4 pins on the outside of the cap? That is what I thought.... I am about to call MSD here in the next 30 minutes so any help between now and then will be helpful.
Thanks.

If you switch to a two wire pickup coil it will plug right in

Thanks for all the great info. I ordered a new HEI distributor on e-bay. Electrical stuff is my weakest point when it comes to cars, but hopefully I'll be able to figure out the installation. It doesn't sound too bad. Where can I find a 12-volt relay? At the parts store or?

Thanks again.

Bosch relays can be purchased at most any parts store, almost all late model cars have a bank of them under the hood,and they even have a wiring diagram right on the case to show you how to hook them up.

Originally posted by FMXhellraiser
Man... Well when they say 4 pin or 7 does that mean the 4 pins on the outside of the cap? That is what I thought.... I am about to call MSD here in the next 30 minutes so any help between now and then will be helpful.
Thanks.

thats the # of pins thats coming out of the module. the end that plugs into the pick up should have 2 pins and on the other end it may have 2,3, or 5 pins. you sure they didnt send a 2 wire pig tail with the module? sounds like you are trying to put a 4 pin module in place of a 5 pin module and you cant do that without changing the out going pig tail.

he is saying his has 5 pins. i think he has a 3 wire pig tail that he is missing that should have come with the new module.