Technical Another carb thread. Help

Happy Memorial Day Hamb'ers!! So once again another carb post.

I bought a Falcon last year with a 302/C4, its got a mild cam, bored something over, Holley Contender manifold, no headers yet... I got really vague information when I got it but it was for a killer price. It runs strong but once the pedal goes down it flutters then catches up. Up the Coronado bridge it starts acting like its out of fuel and drops power fast. It runs a Holley 650 but due to some rust in the lines it's all jacked up. All the lines and tank were replaced and its flowing clean. Instead of a rebuild I'm opting to just replace it. My low end torque is **** and I live in Southern California so gas is approaching $7 a gallon at break neck speeds. I was thinking the Holley 570? Should I go Edelbrock? I drive like an old lady so the engine is more than I'd need. Id rather have something that's a set it and forget it territory. Tuning isn't a huge issue out here. Temperatures in San Diego is pretty much always between 70-80 for most of the year. I've researched to the point of atrophy, so im going to the pros. Thanks!!

 

Just fix the 650! Even tho it is just a tad large for the 302! They have several setting and are a good all around carb!




Bones

 

x2 with Bones. The 650 is a good carburetor with the ability to "tune it" somewhat for your application. It is a little large for the 302, but it may have large port heads in conjunction with the Holley manifold as the builder was going for high RPM breathing. That may indicate why low end is "****" and the 650 is there. How well did it idle?

 

I would go with a Holley 600. You should be able to sell the 650 as a rebuilder for $100
https://www.holley.com/products/fuel_systems/carburetors/street/parts/0-80457S
You can also buy a rebuild kit for the 650 and go that route if you or a friend are comfortable doing it.

 

The 650 must be a double pumper if it is a vacuum secondary curb would be more economical to drive. A 570 or 600 vacuum secondary with a secondary tuning kit will set set you up nicely, never giving you more carb than you need.

 

If you really want a good dependable economic carb, get a 4100 Autolite and rebuild that. They are the best economic carb out there!






Bones

 

Actually the idle is great. That was easy to set up. If im slow on the acceleration its pretty good. If I push it at all it would stumble all over itself before it caught up... I could get the 650 to work for this application but if I save a mile per gallon I would make back my money in a week here in Southern California. Plus I have like 1 shop that does good carb work out here. 99% of the places wont even touch it. The heads look bone stock, rockers and all

 

God I wish. Have you seen the prices of those guys? Best I found was $700. It was sweet though

 

That's what im leaning towards. The 570 isn't a bad price and I really dont mind putting some money into the car. I intend on having this for a long time. The 650 on there is actually in great shape cosmetically and could easily be rebuilt I just dont want to put the money into something that's more than what I needed anyway. The only shop who does rebuilds down here charges $250, so another $250 and I have shiny new carb with a warranty.

 

$700 for a 4100! Oh boy! I’m rich! Lol






Bones

 

https://www.ebay.com/itm/155001466215?hash=item2416cead67:g:OiwAAOSw03xieTH9
Mike

 

What kind of holly is it ?

I had an “ economical “ 650 with manual choke on my 302, put a kit in it and it ran ok . It had no provision for adjusting the floats externally and it was a cheap version of an actual double pumper .

I sold it and bought an edelbrock , slapped it in and went . Minimum tuning and easy to get it just right .


To me it sounds like your boost valves( I think that’s what it’s called ), is blown. Easy to blow it on a holly if you have a
Bac k fire.


The auto light is a tried and tested carb on a sbf and works well . I see them up here as clean used carbs from $200 and down to 50 bucks for a rebuildable core.

I should buy them and advertise them where your livin ‘ I’d be some what better off !!

 

Around here the 2100s and 4100s are ,or were, cheap! I bought more than I could carry the last swap meet I went to….had about $50 in six carbs!








Bones

 

Ha. I remember those days. I had 2 4100's I picked up at a swap meet for $50. I think I ended up just giving them to a buddy.

 

That's what I was reading. The Edelbrock would be smoother and easier out of the box. Considering im not a power user and I wont need much tuning in my neighborhood. I think that may be the route to go. I love the Holley look but I like driving it more. Im wondering it it would cause any issues with a Holley manifold? I dont see how it would but I know these setups can be temperamental

 

Pony car restorers are driving the prices up on them

90% of carb problems are ignition problems! Rule out the 90% before taking on the 10%.

Joe

 

100% agree. I actually swapped it to a DUI system. Cables and all that business went to.

 

Actually what CFM did you go with? Im not sure if a 500 would be to small. I’m not adding anymore performance upgrades and it’s all being tuned down for freeway/economy. Unfortunately I don’t have much info on what’s inside the engine. I know it’s bored over. I ***ume no more than .50, it’s got a loopy cam and heads look bone stock from what I can see

 

I went with a 650 auto choke .

I have a hi-po ford crate motor , roller cam headers edelbrock intake and it’s what the “mustang boys” recommended.


It runs great and fuel mileage is about the same or a bit better thrn the holly .

 

I'm running the 4777 on my SBF. Have the secondary circuit governed by the throttle linkage until fuel prices drop. It's fast enough running on the primary side @ half throttle. If you're running vac secondary you can accomplish the same thing installing a heavy spring. They're VG+ carbs and easy to tune. Pull the bowl & metering plate blow all the p***ages out w/ carb cleaner. If it's been sitting up w/ ethanol in the bowl, it may need a good cleaning & a kit.


Joe

 

If your looking for a replacement, a Summit 500 or 600. Trouble free, won’t leak, Holley internal parts.

 

^2. Those Summit carbs use the annular boosters and are very similar to the 4100’s. Go look at the Y block sites or the Ford truck sites. Guys are using them for drivability and gas mileage, but they make good power too. Not a race carb, but a good street runner. Sounds like your usage.

 

Thanks Mike. I don’t know why guys don’t look to them for street use especially with annular boosters which definitely help in atomization. Ted Eaton has showed us on the dyno their excellent power thru the torque band and near the same hp as a Holley.
As for shiney there are just as good looking as any Edelbrock and come with a dual feed line in the box with a very reasonable price..

 

I purchased a summit 600 carb for my wife’s 1960 T-bird and was very pleased with how it ran. Definitely lived up to all the positive reviews.

 

Had my head up my rear trying to save him a few bucks but automatic trans, stock exhaust, mild cam does calls for a little less carb out of the box if you aren't big into tuning them. Sounds like the case to me after re-reading OP.

Joe

 

I just installed a QFT SL450VS in a buddy's Bronco with a completely stock 302. The only thing needing adjustment was the idle speed. I can't speak to the mileage it produces. For a vehicle that is not performance oriented, I think the 450 is plenty big for a 302. The thing runs great.

 

I agree on the CFM. Holley also make a 450-465 CFM for rock crawlers and similar uses that I have read work excellant for engines up to 350 ci. The average guy spends so little time at even 4000 rpm in his HAMB friendly vehicle it only makes good sense to zero in on an efficient carb that has a great vacuum signal thru the venturii’s for atomization. Thanks jaw22w

 

Yep! I'll bet 90% of our hot rods are over-carbed. I have a sbc 350 +.030, 10.5:1 CR, roller cam, aluminum heads, etc.etc. It has a QFT SL600VS on it. The 600 is plenty of carb for that motor. It spends hours and hours and hours between 1500 and 2500 rpms. Every once in a great while, when I get a hair in my ***, it might spend 3 seconds at 5000 rpm.
It sounds like the OP drives like I do nowadays. Calmed down A LOT from my younger days. The QFT SL carbs, IMHO, adjustable as they are, are the best bang for the buck. I have 3 of them in different CFM models. And if that was my motor I would use the QFTSL450VS. Especially with gas at $7.

 

Damn, thanks for the heads up! I didn't even think of the QFT's as a contender but the reviews and stuff are really good.

 

Damn, Im at a cross between the 500 Summit and the QFT 450 now. Ha. neither were even on my radar but are getting better reviews and numbers than more expensive was I was eyeing to begin with.