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I just picked up a 1973 2wd F-250 with a 390 and a 2bbl carb that leaks a bit of fuel, doesn't like to run when cold, and tends to hesitate a bit when I give it throttle. I don't really need a high performance truck and I go back and forth between picking up a rebuilt 2bbl or going to an Edelbrock aluminum intake and 4bbl carb.
The 2bbl should be a decent reliable carb, right? Aside from the cost of going to the 4bbl, I'm concerned about breaking bolts trying to remove the intake, and the general PITA that it will be. I know I'll get weight savings, but I'm not sure if that combined with the (noticeable?) performance increase is worth it. I don't believe I'll change the cam, however, I've just installed a set of Flowtech headers.
Nothing wrong with a 2brl. Working correctly will do all you want. Though you have headers now down the road who knows.... Here's a link to a post by Aaron-71 who took time to post this great (and best) 2brl manual. You will never regret downloading a complete manual.
I doubt you'd break intake manifold bolts. I've never seen or heard of anyone breaking them. They're not torqued tight anyway. But as always, I'd spray some Kroil or PB on those bolts and let sit overnight. That said, a good 2 bbl is all most of us need. I can't remember the last time I opened up the secondaries on my carburetor. I've got a 4 bbl but only because I wanted the Edelbrock Performer manifold. But I believe there are adapter plates for 2 bbl carbs.
I just picked up a 1973 2wd F-250 with a 390 and a 2bbl carb that leaks a bit of fuel, doesn't like to run when cold, and tends to hesitate a bit when I give it throttle. I don't really need a high performance truck and I go back and forth between picking up a rebuilt 2bbl or going to an Edelbrock aluminum intake and 4bbl carb.
The 2bbl should be a decent reliable carb, right? Aside from the cost of going to the 4bbl, I'm concerned about breaking bolts trying to remove the intake, and the general PITA that it will be. I know I'll get weight savings, but I'm not sure if that combined with the (noticeable?) performance increase is worth it. I don't believe I'll change the cam, however, I've just installed a set of Flowtech headers.
It's a nice truck. There is nothing wrong with the 2 BBLs. If you don't need the extra power, you won't utilize the 4 BBL fully. With all the information available you could probably rebuild your carburetor as long as there is no structural defect in it. Sometime "professionally rebuilt" carburetors are worse than rebuilding your own, depending on your talents. The cold running problem is likely a choke problem; the hesitation is likely an acceleration pump problem; the leak is unknown but could be something simple. You'd have to investigate to determine it.
Nothing wrong at all with a 2 barrel carb, I have seen guys running 650 Holley 2 barrels on some 289's and 390's. Would not even know the difference, unless you keep your foot in it.
Nothing at all. I did not even bother getting a rebuilt carb for my 2bbl on my 360. I just got a rebuild kit, cleaned it all up, and tuned it. It gave me the least problems of everything. Dropping a lifter and jumping the timing chain were my problems. That 44 year-old carburetor ran like a charm. I am switching to fuel injection, but that's because we can afford to now. We want better fuel mileage. If we see 12mpg vs. our previous 7mpg we'll call that a win for the next 150,000 miles! For your needs, 2bbl all the way!
since you have installed headers, put a 2 bbl Holley 500 cfm on it to wake it up. All the old Ford engines where choked in the air flow department. It will breathe a lot better.
As mentioned there is nothing wrong with a two barrel, in fact a 4 barrel will operate on the two front primaries 90% of the time unless your a pedal monster. A typical 4 barrel will be beneficial only above 3000 rpm or so anyway. The engine doesnt start drawing enough cfm until that rpm anyway.
In towing with a 4 barrel with vacuum secondaries you will get some more fuel in the cylinders. Not sure if thats a benefit or not over a 2barrel.
x2 on the imtake bolts, highly unlikely youd break any. If you just did headers and didnt break the manifold bolts id say youll be just fine
It's always cheaper to stick with what you have. But if it were me and knowing the difference it makes I'd switch to 4160 600 Holley Vac secondary and a performer or stock manifold (heavy sucks). The small primaries I feel are more responsive and do better on gas than the 2 barrels. If your old 2 barrel isn't sloppy you could always keep it.
Also I've played with the 500 Holley 2 barrel too a couple years ago and thought it was kind of a hoggish carb. For gas mileage the 2100 did better. They always bring a couple bucks on eBay, I guess they're all that's allowed in some circle track racing. The truck it was on since has been switched to 4 barrel and couldn't be happier.
