64 GMC I1000

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Jethro224

Full Access Member
Joined
May 11, 2020
Posts
107
Reaction score
112
Location
Illinois
First Name
Jim
Truck Year
1980
Truck Model
K20
Engine Size
350
I have a 64 GMC with the 230 straight 6. 420 4spd. 3:54 rear.
Got a couple of questions.

First, I want to upgrade to HEI. The original wire to the coil is a resistor wire. Do I need to run a new, non-resistor hot wire?

I have a deal worked out for a Clifford intake and headers. Supposed to pick em up Saturday.
The deal comes with a Holly 390 4 barrel. I have a Holly 600 available. Which one would you choose?
Stock cam and head. For now...
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
Your going to get a lot of opinions on the carb thing, but here is my two cents. Use the 390. Lots of guys might suggest the larger one, but an engine can only ingest so much. To big of a carburetor will lead to lack of power, and poor fuel economy. If you look at the CFM of the stock carb it's no where 600. You might be able to make a 600 work ok, but the 390 is more in the ballbark for what you have IMO. At the very least if Clifford is recommending the 390, with that engine and their components what wouldn't you at least start with what they recommend?

AS to the HEI, yes you will need a non-resisted 12 volt... In other words a constant 12 volt power supply to the coil. You can bypass the existing resistor and use the same wiring or run a new wire whatever your preference.
 

Jethro224

Full Access Member
Joined
May 11, 2020
Posts
107
Reaction score
112
Location
Illinois
First Name
Jim
Truck Year
1980
Truck Model
K20
Engine Size
350
Thanks.
Well, I'm not sure if 390 is what Clifford recommends. I'm buying the stuff used.
Kinda sounds about right tho. But I like to get others input.

The 64 doesn't have a resistor. It has a resistor wire.
I actually installed the HEI before and had it hooked up to that wire but couldn't get the truck to run right at all. Ended up putting the points back in.
At the time I didn't know it was a resistor wire. When I figgered that out I got to wondering if that might be why.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
29,117
Reaction score
23,995
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Could be a problem with the distributor that you tried. I've got an Impala that the PO installed an HEI distributor and they used the original resistance wire. It actually worked ok, although when I noticed the issue, I ran a dedicated IGN 12v wire to the HEI.
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
Thanks.
Well, I'm not sure if 390 is what Clifford recommends. I'm buying the stuff used.
Kinda sounds about right tho. But I like to get others input.

The 64 doesn't have a resistor. It has a resistor wire.
I actually installed the HEI before and had it hooked up to that wire but couldn't get the truck to run right at all. Ended up putting the points back in.
At the time I didn't know it was a resistor wire. When I figgered that out I got to wondering if that might be why.
I forgot about it being a resistor wire rather than a resistor. It's been a long time since I owned a truck like that, but I still like them!

So I have a soon to be ex-tech at the shop that has a 75 Ford pickup with the 300 I-6 he's running the edelbrock 600CFM on it. He says he's happy with it, but constantly asks me questions about tuning it, he's played with the metering rods and secondary jets to nauseum. He gets pissed and starts yelling if someone says it's over carbureted and that's his problem, and why it has less power than his OEM carb, and his mileage is lower. I can't remember the brand, but he bought the 4 barrel manifold for it online and the website he bought it off of recommended that carb.

Anyhow I'm not sure why I wanted to share that story now.... I guess I'd just relate that to your 230. A quick web search shows most guys seem to be happy putting a Holley 390, Holley 2 barrels, and weber 32/36's on the 230. The Weber BTW is rated at something like 250CFM IIRC. I used to play around with them back in the day, when they were cheap and easy to get parts adaptors and kits for, but IDK if I'd really recommend a weber anymore given there current expense and how hard they can be to get parts. And anyhow you didn't ask about that I just saw a rabbit hole and went down it as I typically do.... I think the Holley 390 would be a good choice.
 

Jethro224

Full Access Member
Joined
May 11, 2020
Posts
107
Reaction score
112
Location
Illinois
First Name
Jim
Truck Year
1980
Truck Model
K20
Engine Size
350
As soon as the weather cooperates with my schedule I'll try dropping that HEI back in again with a unresisted wire and see if I can make it work. I guess I should mention it's an ebay chinesium one...

I looked at the Webers but they are pricy. The 600 Holley is planned to go on my square but I was thinking maybe it would be good for the 6.
Guess I'll probably try the 390 first. I'm new at 6 cylinders. Was always a small block guy.
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
As soon as the weather cooperates with my schedule I'll try dropping that HEI back in again with a unresisted wire and see if I can make it work. I guess I should mention it's an ebay chinesium one...

I looked at the Webers but they are pricy. The 600 Holley is planned to go on my square but I was thinking maybe it would be good for the 6.
Guess I'll probably try the 390 first. I'm new at 6 cylinders. Was always a small block guy.
"I looked at the Webers but they are pricy." Use to be I could pick one up used in need of a rebuild for less than $40 and the new ones were right around $150, so if I got a usedy I could have it rebuilt tuned and adaptor plate for less than $100. Not so anymore. IIRC Weber went completely out of production for a while and it was during that time that they became valuable. When they went back into production $$$

If you want to upgrade from the ebay chinesium consider looking at a Davis Unified ignition.
 

Craig Nedrow

NADAR UNDER THE RADAR
Supporting Member
Joined
Sep 1, 2018
Posts
847
Reaction score
1,528
Location
Washington State
First Name
Craig
Truck Year
1973 (have two), 1985
Truck Model
K10, K20, C20
Engine Size
350, 454, 6.2 Detroit
I have run the clifford/holly setup on a few different rigs. Use the 390 holley, it will have great throttle response as air velocity will atomise the fuel better than the 600 on a stock engine. I have run six cylinders most of my life, and like them. If you put a 194 head on the 230. it will raise the compression, and put in a Isky cam, (I like isky for the chev motors, used a few, Still have a 235 with an isky cam waiting for a nice day to install it into the 55 panel.) Do yourself a favor, buy a holly jet kit, I bought one 30 years ago, and just used it again a couple weeks ago. Many hate the Holley, I think because it is so adjustable, but the 750 on my big block is getting close to fuel injection, instant response, fun to drive. If it has a mechanical choke, hook it up. I have had both electric and mechanical and both work excellant...once you get them adjusted.
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
I have run the clifford/holly setup on a few different rigs. Use the 390 holley, it will have great throttle response as air velocity will atomise the fuel better than the 600 on a stock engine. I have run six cylinders most of my life, and like them. If you put a 194 head on the 230. it will raise the compression, and put in a Isky cam, (I like isky for the chev motors, used a few, Still have a 235 with an isky cam waiting for a nice day to install it into the 55 panel.) Do yourself a favor, buy a holly jet kit, I bought one 30 years ago, and just used it again a couple weeks ago. Many hate the Holley, I think because it is so adjustable, but the 750 on my big block is getting close to fuel injection, instant response, fun to drive. If it has a mechanical choke, hook it up. I have had both electric and mechanical and both work excellant...once you get them adjusted.
I would honestly love to be running a 6. They are great motors, but with my trailer my 305 is adequate, and I'll probably opt for something bigger at the time of rebuild.
 

Jethro224

Full Access Member
Joined
May 11, 2020
Posts
107
Reaction score
112
Location
Illinois
First Name
Jim
Truck Year
1980
Truck Model
K20
Engine Size
350
I have run the clifford/holly setup on a few different rigs. Use the 390 holley, it will have great throttle response as air velocity will atomise the fuel better than the 600 on a stock engine. I have run six cylinders most of my life, and like them. If you put a 194 head on the 230. it will raise the compression, and put in a Isky cam, (I like isky for the chev motors, used a few, Still have a 235 with an isky cam waiting for a nice day to install it into the 55 panel.) Do yourself a favor, buy a holly jet kit, I bought one 30 years ago, and just used it again a couple weeks ago. Many hate the Holley, I think because it is so adjustable, but the 750 on my big block is getting close to fuel injection, instant response, fun to drive. If it has a mechanical choke, hook it up. I have had both electric and mechanical and both work excellant...once you get them adjusted.

Do you know what the compression would be with the 194 head and stock pistons? I was actually wondering about that the other day. I'm not even sure what the stock compression ratio is at this point. Like I said, I'm new at 6cyl.

Got a specific Isky cam recommendation? Torque trumps hp but both are good. A cam is on the list of stuff to do.
 

Craig Nedrow

NADAR UNDER THE RADAR
Supporting Member
Joined
Sep 1, 2018
Posts
847
Reaction score
1,528
Location
Washington State
First Name
Craig
Truck Year
1973 (have two), 1985
Truck Model
K10, K20, C20
Engine Size
350, 454, 6.2 Detroit
Stock compression is 8.5 to one.
There is a young girl that races a 53 chevy rat rod with a 235, (your 230 is a much better engine) and runs a blow through single turbo. Seems reliable, consistent, much faster than stock.
 

Jethro224

Full Access Member
Joined
May 11, 2020
Posts
107
Reaction score
112
Location
Illinois
First Name
Jim
Truck Year
1980
Truck Model
K20
Engine Size
350
This just came in the mail.

I got some studying to do.

Thanks for the links.
I'm not thinking turbo. Just maybe head work. Maybe a 194 head. And a good street cam.
 

Attachments

  • 20220217_143714.jpg
    20220217_143714.jpg
    211.1 KB · Views: 54

Craig Nedrow

NADAR UNDER THE RADAR
Supporting Member
Joined
Sep 1, 2018
Posts
847
Reaction score
1,528
Location
Washington State
First Name
Craig
Truck Year
1973 (have two), 1985
Truck Model
K10, K20, C20
Engine Size
350, 454, 6.2 Detroit
All you would need to do is install 1.94 intake valves (only if you wanted to!) on the 194 head, a 230 (270 @ .05) ballpark cam, and the 390 carb. I also split the exhust, so had dual pipes, a must! Just love a six with twin exhust, a very distinct sound, but will move the HP and probably torque up some in the RPM range. Also I used a Pertronix ignition kit in the existing distributor with there coil, much easier starting and way hotter spark. Miss my sixes, tune up once a year, and so easy to work on and LOTS of room. BTW Used to have a 65 long bed 1/2 ton cherry with a 230, three on the tree, excellent!
 
Last edited:

Jethro224

Full Access Member
Joined
May 11, 2020
Posts
107
Reaction score
112
Location
Illinois
First Name
Jim
Truck Year
1980
Truck Model
K20
Engine Size
350
Oh yeah. Definitely gotta get dual pipes. Love that sound. Been listening on YouTube.

The intake, carb and headers with new dual exhaust will probably be as far as I get this year. And make the HEI work.
In the meantime I can try to round up a cam I like and try to find a head off a 194 to get worked on.

Other stuff on the list is upgrade to dual pot brakes. Finish wiring rehab. Radio! Tie rod and alignment. Maybe some fenders.
 

Latest posts

Forum statistics

Threads
42,140
Posts
910,030
Members
33,642
Latest member
Bhardiman1
Top