Help! Carburetor on 250 I-6

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.

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,194
Reaction score
5,097
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Also, just curious but why the die hard MUST be an I6?
 

JohnTaurus

Full Access Member
Joined
Mar 25, 2020
Posts
152
Reaction score
158
Location
Mississippi
First Name
John
Truck Year
1974
Truck Model
C10 Custom
Engine Size
250 CID Inline 6
Well I meant it as a question to you or anyone. There was a factory MPFI version, just in Brazil in the 1990s, haha! Not exactly available at CarQuest.

I have heard mention for performance intakes that separate the ports, because the factory system has one port per two cylinders. I was just trying to see if you or anyone knew of where I could ffind them. All i can find is a $400+ triple carburetor setup, which is better, but obviously expensive, tricky (ESPECIALLY for a novice on ccarburetors like me!), and not EFI.
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,229
Reaction score
6,209
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
A working carburetor will do everything you need it to do. Just buy a replacement carburetor for a 1980 truck like yours, it came with an electric choke and will bolt on. Just connect your throttle linkage and wire I'm the choke and adjust it.
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,229
Reaction score
6,209
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
I, too, like fuel injection but unless you are going for pure performance or just tossing cash around and want the ultimate turn key experience, a carb will work just fine. Mine is carbureted but one day I'd like TBI, but it's not until I have nothing left to do and have money to piss away because the carb does everything TBI would do for me except for less money and only 1 electronic device
 

JohnTaurus

Full Access Member
Joined
Mar 25, 2020
Posts
152
Reaction score
158
Location
Mississippi
First Name
John
Truck Year
1974
Truck Model
C10 Custom
Engine Size
250 CID Inline 6
Also, just curious but why the die hard MUST be an I6?

Fair question.

It was pretty much why I bought the truck in the first place. I love inline 6s, especially American ones. Aside from a vintage Inline from an American truck, I was actually looking for a late-80s-96 F-150 with the 300 6.
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,229
Reaction score
6,209
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
My f150 has a 300. It's what's inspiring me to PUT in a 250 or a 292 in my truck! Can't go back to a V8 after that. Just can't.
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,229
Reaction score
6,209
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
6 in a row, you're ready to tow. 8 in a v, your old lady is coming home with me
 

JohnTaurus

Full Access Member
Joined
Mar 25, 2020
Posts
152
Reaction score
158
Location
Mississippi
First Name
John
Truck Year
1974
Truck Model
C10 Custom
Engine Size
250 CID Inline 6
My f150 has a 300. It's what's inspiring me to PUT in a 250 or a 292 in my truck! Can't go back to a V8 after that. Just can't.

See, you get it. I've had two Ford cars with Inline 6s, and (aside from carburetor issues on one especially!) they were smooth, economical and so reliable. When searching for me a truck, an Inline 6 was the idea.

The 1983 Mercury Zephyr GS had the benefit of being tuned by a Lincoln-Mercury dealer technician, and it ran amazing. That guy could make a 1973 Continental run as smooth as a 2020. Genius with those emissions-strangled carburetors. Too bad I couldn't find him when I had my 1978 Zephyr Z-7 later on. The 6 was strong, but carburetor after carburetor, adjustment, rebuilds, repairs, it never ran right after the original went out, and I was forced to sell it for peanuts because I was moving and couldn't tow it 3,000 miles.

That's why I hate carburetors. I've had vehicles I loved that I could do nothing with because of carburetor problems. All the combined money Ive wasted fixing the Z-7's persistent carburetor issues could have probably imported me an Australian alloy head, manifolds (and use American EFI parts) from an 80s/90s Falcon and I'd still have it.
 

WamboJambo

Full Access Member
Joined
Jul 28, 2019
Posts
115
Reaction score
180
Location
NC
First Name
James
Truck Year
1978
Truck Model
C10
Engine Size
250
Here are the pics of the lonely disconnected vacuum hose. Its the one casually laying across the inner fender, over the options label for the purpose of this picture.
Could it go to the EGR? Carb?

I believe this would be a vacuum diagram for your vehicle.

You must be registered for see images attach


Personally though, I see that your fuel bowl vent on your carburetor is unplugged, and when I undid all the hoses on my 250 I had a line going from there to the evap canister. Possibly related?
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,194
Reaction score
5,097
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Well, I'm going big iron in my tow vehicle. We had a late 60's short bed step-side with an inline 6 and three on the tree when I was a kid and it was a gutless pile of junk. It was probably just that my dad didn't know what he was doing with it and my brother wrecked it before I got a chance to really use it, but I'll take my Vortec MPFI 454 over a I-6 250 any day for towing.

Heres an interesting inline 6 forum I found when looking around the interwebs. https://www.inliners.org/ubbthreads/ubbthreads.php?ubb=cfrm

This book also looked really informative for I-6 performance improvements. https://www.amazon.com/Chevrolet-Inline-Six-Cylinder-Power-Manual/dp/1931128278/ref=dp_ob_title_bk
 

JohnTaurus

Full Access Member
Joined
Mar 25, 2020
Posts
152
Reaction score
158
Location
Mississippi
First Name
John
Truck Year
1974
Truck Model
C10 Custom
Engine Size
250 CID Inline 6
I believe this would be a vacuum diagram for your vehicle.

You must be registered for see images attach


Personally though, I see that your fuel bowl vent on your carburetor is unplugged, and when I undid all the hoses on my 250 I had a line going from there to the evap canister. Possibly related?
Awesome diagram! Saving that image!

Yes I will plug it in to there, I was thinking about doing that, but I'm so afraid of plugging something in wrong. I very much appreciate that!

(
 

JohnTaurus

Full Access Member
Joined
Mar 25, 2020
Posts
152
Reaction score
158
Location
Mississippi
First Name
John
Truck Year
1974
Truck Model
C10 Custom
Engine Size
250 CID Inline 6
Re: EFI. That is my eventual goal for this truck, along with likely an NV3500 transmission with hydraulic clutch conversion to replace the current 3 speed manual.

My immediate goal is to get it running/starting/driving well enough to keep it in service in the meantime.
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,229
Reaction score
6,209
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
A mpfi vortex 454 would have a different comparison to a 450 inline 6 for example. At a certain point you just need more ci and a v8 can fit more ci in a smaller space hence the common ness of them. A small inline 6can hold it's ground really well to V8 especially with modern fuel injection and transmissions that keep them in the optimal torque curve. Unfortunately a lot of inline 6s still chugging are mated to old 2 and 3 speed trans while modern v8s got direct injection and 8 to 10 speed transmissions. With the exception of Cummins in dodges of course
 

WamboJambo

Full Access Member
Joined
Jul 28, 2019
Posts
115
Reaction score
180
Location
NC
First Name
James
Truck Year
1978
Truck Model
C10
Engine Size
250
Awesome diagram! Saving that image!

Yes I will plug it in to there, I was thinking about doing that, but I'm so afraid of plugging something in wrong. I very much appreciate that!

(
I will say, it definitely can't hurt to just plug it in there; all it'll do is dump evaporated fuel vapors into the charcoal canister.
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,229
Reaction score
6,209
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
And the reason I like my inline is it's got monster torque in my light 2wd truck, gets ok mileage, and is infinitely simpler because 1 head, easy spark plugs, engine bay space, and it just so happens to refuse to die or stop running(engine basis, not inline basis)
 

Forum statistics

Threads
42,159
Posts
910,336
Members
33,656
Latest member
Bowers31
Top