Hi all,

I'm planning to try another carb again here soon. I know I could be happy with lots of the carbs I've tried if I wasn't so darn picky, but I am. I drive my Bronco every single day around town, on the highway, in 10* in winter and 110* in the summer, as well as off-roading and camping, so I really do need a mix of reliability, performance, responsiveness, and definitely gas mileage.

So far, I tried the Holley 390cfm, but I simply just could not get any gas mileage out of it (regularly got 10 - 12 on the open road), and then tried a Holley 600cfm which oddly got great gas mileage (about 17 - 19 on the open road and 15 in town), but had issues with drivability. My most recent carb was the Holley spreadbore 650cfm 80555c. It did reasonably well, but Holley really tuned the whole thing very rich, and I was constantly fighting to lean it out.

So, I want to try something new, again.

I'm really heavily leaning toward the 580cfm QuickFuel carb. Every review I read on them is just glowing and singing their praises, so it really intrigues me. I love the idea of how adjustable they are with changeable air bleeds, power valve restrictions, idle fuel restrictions, secondary metering block, etc. etc. Lack of adjustability is something I'm tired of. Plus, I have picked up and invested in a LOT of Holley tuning parts, so it'd be nice to keep being able to put those to use.

However, I'm worried that even if I get it tuned in right, it's still going to have soggy performance simply due to it being a big carb. Dunno. I really do wish QuickFuel made a 450 - 500cfm version of their tunable carb.


A recent idea I had was to purchase a Holley 1848 465cfm 4bbl. That just seems about the right size for our engines. Get a secondary metering block for it, and pay some local place to drill it all out and thread it for changeable air bleeds just like the QuickFuel. That way, I'd have the adjustability, as well as a more reasonable cfm. However, I'm just worried about getting another used carb (don't have the money to buy a new 465 as well as have all the work done).

What do you all think? Which would be the better route? Opinions?

 

Adapter plate and a Motorcraft 2100 or 2150?

 

I've been curious about how a 2bbl would work, but I have the DP intake, so it has to be a 4bbl.

 

What about on the wife's Bronco?

 

I'm not sure what the deal is with hers. It likes any carb. Right now it has a Holley 600 on it and gets 13 in town and 17 on the highway, and drives really well. A couple issues here and there, but nothing major.
Probably the 3.55 gears and Offenhauser C.

I've thought about trying a 2bbl on it, but if it's not broke, don't fix it.

 

Happy wife, happy life!

 

Well, I know I just asked this question, but I already pulled the trigger.
I found a really nice 1848 465 cfm Holley on eBay for $115 shipped.

Going to get a rebuild kit, a secondary metering block, and call around and see what someone would charge to modify it for screw in air bleeds.

Then contact Holley and see what the stock air bleed/restriction sizes were for a good starting point.

I'd love for this to be the last one!


Stock settings:
57 main jet
134-3 secondary metering plate. equivalent to about a 55 jet
8.5 power valve
.025 squirter
green secondary actuation spring




My 5000th post!

 

Lol, she loves her Bronco. It's in gorgeous condition too.

 

I've never seen specs but that Quick Fuel 580 carb should have no problems at any RPM range on a 300. They're so well made and have very well designed boosters. Sealed bearing throttle shafts, screw adjustable secondaries. I have one of their double pumpers on my Mustang and it runs fine down low despite only pulling ~10" of vacuum at idle (244° duration at .050" cam).

 

They seem like an extremely well built carburetor. The sealed throttle shafts would be really nice.
I heard from them today that they're in the works of designing a smaller one that's in the 400cfm range. It's supposed to be out mid-2015.
At least, that's what the tech guy said today.

I'll keep my eye out for it, and in the mean time, see what I can do with this 465.

 

About time they got on the 4 and 6 cylinder bandwagon.

 

Yeah, I think that's pretty exciting.

 

Hmmmmmm...I wonder if the Holley Shop can fix the metering blocks with screw-in bleeds...

 

Well, the local carb shop said they charge $55/hr and figure they can get it done in about 30 minutes. That's just for the 8 air bleeds on top.

As for the metering block, I'm going to get the secondary metering block kit from allcarb and then QuickFuel's adjustable metering block.
It has adjustable idle fuel restrictions (probably the thing I screw with the most for gas mileage), as well as power valve restrictions.

METERING BLOCK CONVERSION WITH TRANSFER TUBE

Primary Billet Metering Block Standard Calibration W/ Spark 1850,3310,4776,4777,4778,4779


I think after that, there shouldn't be anything I can't tune on it to get it where I want.

 

Good for you, AB. I hope it works out for you. I think that will be a great carb for you.