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Old 04-04-2015, 05:48 PM   #1
natedogg
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Summit HEI upgrade kit

Thanks for any and all replies. I have learned so much from the great info here. I want to upgrade the HEI in my 85. Truck has the original numbers matching 305 with Edelbrock intake and carb. Everything else is stock. When the truck is sitting still ideling there is a slight stumble in the exhaust note. I'm thinking the kit will solve this? Other than that the truck runs really good. Has anyone used this kit or something similar? Do I need all of the kit?

http://www.summitracing.com/parts/su...olet/model/c10
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Old 04-04-2015, 06:18 PM   #2
dragonball98312
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Re: Summit HEI upgrade kit

Have you looked into doing the HEI relay upgrade? It uses a relay to give a full 12v charge to the distributor. Id recommend trying that before buying anything else.
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Old 04-04-2015, 06:29 PM   #3
enaberif
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Re: Summit HEI upgrade kit

HEI kits are really a snake oil more than anything. There really is no need for fancy requirements in a relatively stock engine or even a mild build.

If you have a stumble you need to look at other places first rather than a upgrade kit.
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Old 04-04-2015, 07:25 PM   #4
Bigstevex4
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Re: Summit HEI upgrade kit

I got a hole HEI distributer for my six for that much. That took care of the same problem the bush gets wore in distributer. This kind of stuff I think of how many million times that thing has been around in 160 thousand miles. Or 260 thousand?
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Old 04-05-2015, 10:04 AM   #5
gmachinz
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Re: Summit HEI upgrade kit

My experience with odd stumbles too especially with high mileage motors no matter how well they're maintained, is the slack in the link type chain and wearing of the nylon coating off the cam gear. The nylon "pieces" as they wear off usually collect in the oil pump pickup tube creating low oil pressure. Most people never stop to think that the majority of "running" issues can be traced directly to a worn timing set-nothing can compensate for it other than spending a weekend dropping your oil pan, pulling your timing cover off and replacing it.

A good HD double roller set from Dynagear or Cloyes is about $40-50 and its well worth the effort. IMO if your motor is stock and has 75K+ miles, I'd suggest a new timing set.
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Old 04-05-2015, 05:47 PM   #6
MikeB
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Re: Summit HEI upgrade kit

Quote:
Originally Posted by natedogg View Post
Thanks for any and all replies. I have learned so much from the great info here. I want to upgrade the HEI in my 85. Truck has the original numbers matching 305 with Edelbrock intake and carb. Everything else is stock. When the truck is sitting still ideling there is a slight stumble in the exhaust note. I'm thinking the kit will solve this? Other than that the truck runs really good. Has anyone used this kit or something similar? Do I need all of the kit?

http://www.summitracing.com/parts/su...olet/model/c10
As someone said above, I doubt the HEI is your problem. It was a very good design, and still is. And parts are cheap and available everywhere.

I don't understand the comment above about using a relay, because an HEI is wired to get full battery voltage, minus any losses through wire, switches and connectors, of course.
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1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes.
1982 C10 SWB -- sold
1981 C10 Silverado LWB -- sold, but wish I still had it!
1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming.
Retired as a factory automation products salesman.
Worked part-time over the years for an engine builder and a classic car repair shop.
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Old 04-05-2015, 06:09 PM   #7
Jake Wade
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Re: Summit HEI upgrade kit

Has anyone been able to find a source for the little bushings that go between the advance weight and pin?

NAPA use to offer them in the Echlin line but, not anymore, been discontinued.
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Old 04-05-2015, 08:01 PM   #8
dragonball98312
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Re: Summit HEI upgrade kit

Quote:
Originally Posted by MikeB View Post
As someone said above, I doubt the HEI is your problem. It was a very good design, and still is. And parts are cheap and available everywhere.

I don't understand the comment above about using a relay, because an HEI is wired to get full battery voltage, minus any losses through wire, switches and connectors, of course.
yeah i looked into it after i posted it. if his was factory hei it shouldnt matter. the reason it helped me in my 77 is cause my trucks running a full harness from a 73 that was originally points. so the relay helped me when i switched to hei. my bad
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Old 04-05-2015, 09:05 PM   #9
gmachinz
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Re: Summit HEI upgrade kit

Quote:
Originally Posted by Jake Wade View Post
Has anyone been able to find a source for the little bushings that go between the advance weight and pin?

NAPA use to offer them in the Echlin line but, not anymore, been discontinued.
Whenever I overhaul the HEI's I just use the Accel curve kits-them come with spring set, weights and nylon bushings. They're about $8-10 at any O'Reillys parts store.
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Old 04-05-2015, 09:05 PM   #10
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Re: Summit HEI upgrade kit

I also use an adjustable vacuum advance as well.
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Old 04-05-2015, 09:55 PM   #11
ron350
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Re: Summit HEI upgrade kit

Jake Wade I found these two part numbers.
AC Delco D337A
http://parts-catalog.acdelco.com/cat...tock_check.php

Standard DG54 at Rock Auto
https://www.rockauto.com/catalog/x,c...,parttype,7116

Gmachinz what is the part number of that Accel kit?
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Old 04-05-2015, 11:04 PM   #12
enaberif
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Re: Summit HEI upgrade kit

Quote:
Originally Posted by dragonball98312 View Post
yeah i looked into it after i posted it. if his was factory hei it shouldnt matter. the reason it helped me in my 77 is cause my trucks running a full harness from a 73 that was originally points. so the relay helped me when i switched to hei. my bad
This is because the wire from the bulkhead connector uses a resistor type wire which doesn't give full 12v to the HEI distributor.

This leads to a person doing 1 of 2 things..

The first thing is just running a 12v wire minimum 12g from the bat terminal to the fuse block.

The second and which I think is the best option is getting a new terminal and crimping a new wire and feeding it directly in place of the resistor wire.

Option two is what I did since the PO(s) horribly hacked the hei together in my truck.
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Old 04-05-2015, 11:10 PM   #13
gmachinz
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Re: Summit HEI upgrade kit

Quote:
Originally Posted by ron350 View Post
Jake Wade I found these two part numbers.
AC Delco D337A
http://parts-catalog.acdelco.com/cat...tock_check.php

Standard DG54 at Rock Auto
https://www.rockauto.com/catalog/x,c...,parttype,7116

Gmachinz what is the part number of that Accel kit?
31041 is the Accel part number for the HEI curve kit. It has 3 sets of springs which are color coded to provide more or less tension. This let's you bring it total timing sooner or later in your RPM range.
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Old 04-05-2015, 11:16 PM   #14
MikeB
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Re: Summit HEI upgrade kit

Quote:
Originally Posted by enaberif View Post
This is because the wire from the bulkhead connector uses a resistor type wire which doesn't give full 12v to the HEI distributor.

This leads to a person doing 1 of 2 things..

The first thing is just running a 12v wire minimum 12g from the bat terminal to the fuse block.

The second and which I think is the best option is getting a new terminal and crimping a new wire and feeding it directly in place of the resistor wire.

Option two is what I did since the PO(s) horribly hacked the hei together in my truck.
And then there are some 60s Pontiacs that used a couple feet of resistance wiring burried in a harness under the dash. Lots of fun!
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1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes.
1982 C10 SWB -- sold
1981 C10 Silverado LWB -- sold, but wish I still had it!
1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming.
Retired as a factory automation products salesman.
Worked part-time over the years for an engine builder and a classic car repair shop.
Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then!
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