When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi, I'm new to carb engines, but reading around I'm understanding that replacing a carb is dependent on many factors, i.e. tranny, engine, etc. So reading around I've seen these are the some of the most common carbs for the 390. I just want to make sure I'm on the right track to getting a new carb.
I have, from what I was told, a 390 (4spd manual) with a 2 barrel. The engine turns over, but can struggle start right away. The previous owner was told to replace the carb and get a 4 barrel, nearly identical pricing and much better output.
So from what I've gathered, I'm debating on either the Autolite 4100 or Holley 4160, not sure about adjustable or non-adjustable float. I figure 600cfm is adequate. Seems like the Autolite is the "go-to" and the Holley is better for tuning.
Is there anything else I should take into consideration replacing the carb?
You do realize you will need to source a intake from somewhere. Since you say it can struggle to start that has nothing to do with it being 2bbl or 4bbl. I would solve the struggle to start problem first.
I did not. So I would be better off getting a carb/intake manifold combo? I do want it to make a little more power and figure getting a 4bbl would be a good start. I was planning on replacing the vacuum lines to get rid of any line leaks, if there are any. Plus it would tidy up the bay a little. The air filter was recently replaced by the previous owner.
Just swapping to a 4 barrel will not show you much of anything. Rebuild the engine, add headers, cam, do head work when adding the 4 barrel if you want to see a difference.
I think I'd pull a few plus and see what they look like. What does the plug wires look like? Are they cracked and dry? Depending on they year, points? The spark plugs will help tell you what is going on.
Struggling to start right away sounds like the timing is set to far advanced.
So check the timing, Since the vehicle is new to you I'd do a compression test to see if all the cylinders are in good shape, as the unleaded gas burns out the exh seats..
orich
First, welcome aboard! I read your intro post and feel inclined to include a picture of your truck.
Second, kudos for taking a 30 year step backwards in technology. I want to point out, that fuel injected vehicles start much easier than carbureted vehicles.
To slow things down even more, During the '70s, Ford decided to let the fuel drain back to the tank, so it would not evaporate into the atmosphere. It took a lot of reading for me to understand why my "new" fuel pump let the carburetor go dry.
So, if your engine cranks over easily, but takes a few seconds to start, life is good!
First, welcome aboard! I read your intro post and feel inclined to include a picture of your truck.
Second, kudos for taking a 30 year step backwards in technology. I want to point out, that fuel injected vehicles start much easier than carbureted vehicles.
To slow things down even more, During the '70s, Ford decided to let the fuel drain back to the tank, so it would not evaporate into the atmosphere. It took a lot of reading for me to understand why my "new" fuel pump let the carburetor go dry.
So, if your engine cranks over easily, but takes a few seconds to start, life is good!
The fuel return was, I believe only on the f100's for the most part, as my 71 f250 don't have any of the return vapor setup on it an no vented gas tank.
Some where in the mid 70's the f250 had the smog pump and a egr valve on them. gutless 360/390 V8
Orich
My 71 f250 with HEI dizzy starts as good as my 06 Nissan 95% of the time.
Thank you all for the help! I got a hold of the mechanic, a week ago, who worked on the truck last and I asked him if the truck had any start up issues prior, he said a compression check would be a good idea and that the carb, 100%, needs to be replaced.
Since I talked to him, the truck stopped turning over. So I think I will replace the carb, intake manifold, and the headers too. See if that helps any bit to getting her started up. The truck had a "tune-up," replacing the plugs/wires/etc and all within the past year.
As for the carb and intake manifold, I am bit unsure which to go with. I don't plan to rebuild the motor within the next year, so something adequate would be fine for now. As for the headers, I was leaning towards the flowtech, very cheap, but I read around and they seem to have fitment issues. I think I will go with the Headmen 89100. Inputs on the carb/intake? Maybe just rebuild the carb?
Hmm I think you need to first to get it to turn over and start before throwing money at around it. Header are nice but you get what you pay for when it comes to headers.
Plus it will cook the starter in time then your starter fails you. And if it's an auto tranny you can't push it to get started to get it home. It's then Tow truck time!
Plus now days most all headers will trap the starter in place.
Then you'll have to remove or drop the header to pull the starter out.
With so many company's making mini starter this is best way to go with headers.
Back in the day most company's built headers that did not trap the starter. As a mini starter cost a lot of bucks back then.
Now in todays world china makes everything and much cheaper some stuff good and not so good.
Orich
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
