HEI Ignition

Has anyone put a regular Olds HEI ignition system on their GMC? If so,
what particular model/years should be used? Benefits versus drawbacks?
Other considerations?

Any help would be most appreciated!
 
Patrick:

I believe it was in 1975.

Paul Bartz

> From: Patrick Flowers [SMTP:patri63]
> Sent: Monday, July 13, 1998 11:32 AM
> Subject: GMC: HEI Ignition
>
> What year did GM start putting the HEI on the 455?
 
>
> Has anyone put a regular Olds HEI ignition system on their GMC? If > so, what particular model/years should be used? Benefits versus
> drawbacks? Other considerations?

Ralph,

This is a very popular conversion for the older Oldsmobiles. The
biggest problem on our motorhomes is that the larger HEI distributor
interferes with the air cleaner. You can't use an aftermarket air
cleaner due to clearance problems with the engine cover. You either
need to "remodel" the original air cleaner with a hammer or find an air
cleaner off a later model motorhome(or toronado).

The swap is pretty straightforward and the procedure was even outlined
in a post here several months back. IIRC, you need to pull 12V off the
IGN post of the fuse block(the factory points wiring is only 6V and is
not heavy enough for the HEI) and the poster recommended 10AWG wire.

I was thinking of going with the petronix module, which fits inside the
original distributor, but parts availability on the road could be
tough. Instead of picking up an HEI module or coil at the nearest
Autozone, I'd have to get a replacement pertronix module FedEx'd to
whereever I was stranded(or carry a spare on board). The petronix also
wouldn't require any wiring changes.

Patrick
- --
Patrick Flowers
Mailto:patri63

The GMC Motorhome Page
http://www.gmcmotorhome.com
 
Thanks Paul,

I should have known that. My father's is a 75 and it has HEI.

Patrick

>
> Patrick:
>
> I believe it was in 1975.
>
> Paul Bartz
>
> > From: Patrick Flowers [SMTP:patri63]
> > Sent: Monday, July 13, 1998 11:32 AM
> > Subject: GMC: HEI Ignition
> >
> > What year did GM start putting the HEI on the 455?

- --
Patrick Flowers
Mailto:patri63

The GMC Motorhome Page
http://www.gmcmotorhome.com
 
picksam Yes, I have put an electronic system without
the computer ( vac advance). Works great and is simple. Good performance
and power with good gas mileage. I travel a lot between FL and MI; many
steep hills and I can actually gain speed up most as long as I begin around
65+ MPH. 1975 OLDS Toranado. You may want to got to acel for an upgrade.
Mine is a 1974 Md'l electrondon or so the title says with 42Kmi.

- ----------
> From: Ralph Edelbach
> To: gmcmotorhome
> Subject: Re: GMC: HEI Ignition
> Date: Monday, July 13, 1998 11:50 AM
>
> Has anyone put a regular Olds HEI ignition system on their GMC? If so,
> what particular model/years should be used? Benefits versus drawbacks?
> Other considerations?
>
> Any help would be most appreciated!
 
Patrick:

I'm not familiar with the below.

Is that a brand or type name? What advantage do you see to it vs. the
one from Dick Patterson, which has an advance system optimized for our
coach?

Paul Bartz

> From: Patrick Flowers [SMTP:patri63]
> Sent: Monday, July 13, 1998 4:00 PM
> Subject: Re: GMC: HEI Ignition
>

>
> If you're thinking of updating the distributor, consider the one Dick
> Patterson, http://www.paterson-gmc.com/~gmc/motorhome.html has
> available. He modifies it for the GMC.
>
>
> If I can find a post 75 air cleaner, I'll go the HEI route. If not,
> I'll probably use the pertronix.
 
>
> I'm not familiar with the below.
>
> Is that a brand or type name? What advantage do you see to it vs.
> the one from Dick Patterson, which has an advance system optimized
> for our coach?

Pertronix is a brand name for a module that replaces the
points/condensor set in a standard distributor that works with existing
wiring and coil. You don't get the higher voltage of the HEI
system(with factory coil), but you do get the constant dwell angle,
which is the major advantage of HEI(with points, performance is best
after you install and properly set new ones and deteriorates from that
point). The advantages of using the pertronix for me(73 with original
distributor) are that it uses factory wiring and doesn't require a
different air cleaner.

Patrick
- --
Patrick Flowers
Mailto:patri63

The GMC Motorhome Page
http://www.gmcmotorhome.com
 
My GMC chassie was started in late 74, and finished in Feb. on 75 with the
breakerless ignition. One of my tech. manuals states the 455 breakerless
ignition first application to be started in 74.
- -----Original Message-----
From: Bartz, Paul
To: 'gmcmotorhome'
Date: Monday, July 13, 1998 10:53 AM
Subject: RE: GMC: HEI Ignition

>Patrick:
>
>I believe it was in 1975.
>
> Paul Bartz
>
>> From: Patrick Flowers [SMTP:patri63]
>> Sent: Monday, July 13, 1998 11:32 AM
>> Subject: GMC: HEI Ignition
>>
>> What year did GM start putting the HEI on the 455?
 
My orig 74 had breakers; but it was actually manfg in 73. for what it's
worth.
- -----Original Message-----
From: JRBIAVA
To: gmcmotorhome
Date: Monday, July 13, 1998 9:19 PM
Subject: Re: GMC: HEI Ignition

>My GMC chassie was started in late 74, and finished in Feb. on 75 with the
>breakerless ignition. One of my tech. manuals states the 455 breakerless
>ignition first application to be started in 74.
>-----Original Message-----
>From: Bartz, Paul
>To: 'gmcmotorhome'
>Date: Monday, July 13, 1998 10:53 AM
>Subject: RE: GMC: HEI Ignition
>
>
>>Patrick:
>>
>>I believe it was in 1975.
>>
>> Paul Bartz
>>
>>> From: Patrick Flowers [SMTP:patri63]
>>> Sent: Monday, July 13, 1998 11:32 AM
>>> Subject: GMC: HEI Ignition
>>>
>>> What year did GM start putting the HEI on the 455?
>
>
>
>
 
Guess I was luck with coach # 496!!!!

>>What year did GM start putting the HEI on the 455?
>
>Patrick,
> Mid 1975. (Starting at serial Number TZE1X5V100472, or about 75 coaches
>after mine. Not sure if I'm disappointed or relieved.)
>
>Rick Staples
>
>
 
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