HEI Ignition

84'GMC4x4

Member
anyone know the quickest way i can tell if i have HEI? my truck is an 84 GMC w/350, i noticed the other day that my cap & rotor are badly in need of replacement, i would like to upgrade to HEI if it's not too much $/hassle.
any advice/comments welcome
thanks,
Greg
 
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8

84'GMC4x4

Member
yes, the coil is in the cap,so i guess i have HEI. thanks for the replies guys.

John, i will be replacing the coil too, thanks for the help.

Greg
 

UNCLE BOB

Member
HEI

I would recomend buying a new(Control Module),just in case.I had a blazer,in which the control mod. blew TWICE, both times on I 95 and when it goes ,your truck is DEAD. I pulled my distributor,found a chiped gear. New dist."cheap" module's $175.00 x 3= OUCH. I never left home with out one.
 

mike reeh

Senior Member
uncle bob what exactly does the electronics dying have to do with chipping a gear? and what gear chipped? the dist. drive gear??

mike
 

UNCLE BOB

Member
H E I

Yes the dist. gear on bottom of shaft,When it hit the bad spot it increased speed from missing the chipped spot,inturn increasing the juice and burning the module until it could'nt take anymore and blew.which was about every week and a half. Twice.Until my buddy said "let's change the dist." And there it was.
 

Alan

PlowSite.com Addict
Re: H E I

Originally posted by UNCLE BOB
Yes the dist. gear on bottom of shaft,When it hit the bad spot it increased speed from missing the chipped spot,inturn increasing the juice and burning the module until it could'nt take anymore and blew.which was about every week and a half. Twice.Until my buddy said "let's change the dist." And there it was.
I'm a little dense, how did having a bad tooth on the drive end make the distributor "increse speed"? Since on one tooth (on a helical cut gear) is ever carrying the whole load, how did it affect anythign unless it was totally missing? Even then I can't see how it affected voltage through the module. If it was missing so much gear that it was affecting the electronics, how did it manage not to jump timing by one tooth for every rotation of the distributor? There's something funny here and I suspect there was something else wrong with your distributor.
 

UNCLE BOB

Member
HEI

I dont know,but that is what my buddy said.It was skipping,wobbling or something.All i rember is the gear on bottom of dist. was damaged,we replaced the dist. and never had another problem! Sorry If my description of the problem was off.
 

RTallday

Member
Location
Long Island, NY
I believe that HEI was an option for a while, because i had a '76 C-10 and it didnt have an HEI dist, it had the regular cap and coil. My 79 K-20 has HEI and it is listed on the option sheet, and it was origionally made by ACCEL. There is also a sticker on the fire wall right above the distributer. Just thought i would share that.

-Rich
 

75

PlowSite.com Addict
I'm not sure if HEI was optional from '75 on (my 1975 GMC had it when I bought it, but it wasn't the original engine) - I'm wondering if your C-10 had an older engine swapped into it at one time? Just curious.
 

RTallday

Member
Location
Long Island, NY
The engine in the 76 c-10 was origional. Im sure of it. Thats why i think HEI was an option. As i said, im not positive, but i thought i would throw that in there.

-Rich
 
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