A lot of Carb

[Elis69falcon]

I just bought a carb adapter to put a Holley 2BBL on my 200 Straight 6. I bolted the carb up and it runs amazing! My father had a new Holley that has been needing a home. The only problem is, the carb is 500 cfm... It won't calm down. Is there any way i can find out an appropriate jet size? I could always go to a smaller carb... but i would rather save a couple hundred bucks and jet it down. any input would be appreciated!

 

[ludwig]

You have way too much carb on a 200 cube engine. Max for these is about 350 cfm. Now there are those who have run bigger carbs successfully but they did a lot of mods.

 

[64 200 ranchero]

i have a holley 500 cfm on my 200 and it runs great with no mods, eccept for my msd and header, my gas mileage didnt go down that much either

 

[JackFish]

Search posts from wsa111, a no longer active member,
He researched and got his 500 running very well using a wideband.
It takes some mods, but it can be done.

You can start here:
viewtopic.php?f=1&t=29740&p=215106&hilit=holley+tuning#p215106

 

[Elis69falcon]

64 200 Ranchero, what jets do you have in your 500 cfm?
Jackfish, Thanks!

 

[ludwig]

What I said.

 

[Elis69falcon]

Ludwig, I'm 18 and about to pay for 4 years of college... trying to save some

 

[bubba22349]

Is there any way i can find out an appropriate jet size?

Low buck way you can do it is by reading the plugs you want a nice light tan color!

 

[64 200 ranchero]

64 200 Ranchero, what jets do you have in your 500 cfm?
Jackfish, Thanks!

they are stock, the carb runs a little rich but smooth, did you try to run the carb on your engine, when i put mine on the idle was way too high no matter how i adjusted it, then i found that i had a vac leak, since then it runs good idle is arround 700 rpm and it does not bogg out off the line, what type of ignition do you use?

 

[powerband]

'Presume you are runnng a 500 CFM 2300 series 4412. Anyway, the 350 CFM 2300 series 7448 is widely available ( meaning fairly cheap) and will be milder with better low to mid throttle. Mild 200 with 350 CFM 2bbl is still more than adequate but should be less eye watering than the 500 8)

Nice to hear it's running well, how did you make up the linkage -any pics?

Habe fun

 

[Elis69falcon]

64 200 Ranchero, what jets do you have in your 500 cfm?
Jackfish, Thanks!

they are stock, the carb runs a little rich but smooth, did you try to run the carb on your engine, when i put mine on the idle was way too high no matter how i adjusted it, then i found that i had a vac leak, since then it runs good idle is arround 700 rpm and it does not bogg out off the line, what type of ignition do you use?

I have the stock ignition in it right now but i plan to upgrade to duraspark... I have it on the engine now with no throttle cable on it... It runs smooth and sounds nasty i just cant get it to idle slower. where was your vac leak? Im also curious to the mpg you get...

 

[Elis69falcon]

'Presume you are runnng a 500 CFM 2300 series 4412. Anyway, the 350 CFM 2300 series 7448 is widely available ( meaning fairly cheap) and will be milder with better low to mid throttle. Mild 200 with 350 CFM 2bbl is still more than adequate but should be less eye watering than the 500 8)

Nice to hear it's running well, how did you make up the linkage -any pics?

Habe fun

Funny you should ask, I bought the Lokar kit, kickdown, throttle cable, and Bracket, which came this afternoon. I am having significant difficulties just looking at lack of valve cover clearance... any light to shed on a solution?

 

[64 200 ranchero]

the leak was where the addapter meets with the intake, i fixed it by putting some oil resistant silicone on the gasket, also try backing the fast idle screw off all the way and adjust the idle mixture till you get the proper idle, the ds2 should also help

 

[powerband]

Funny you should ask, I bought the Lokar kit, kickdown, throttle cable, and Bracket, which came this afternoon. I am having significant difficulties just looking at lack of valve cover clearance... any light to shed on a solution?

You can modify the OEM pedal and rod linkage. Simplest setup is to use an over the valve cover bracket like used on Maverick/Comet/Granada and many other cable throtttle carb'd Fords of the 70/80's. You could also fab something similar. The Lokar kit and some used parts should work..


Over the VC 7448 and H/W setups:

<> <>


Modded OEM pedal/rod setup for H/W 2bbl annd Tri-power with 2Bbl center:

<>

 

[rbohm]

8) it isnt just the jetting you have to deal with, but also the power valve opening point as well, among other things.

 

[drag-200stang]

There are a lot of misconceptions about how a carb works. A larger CFM carb will not just make the engine idle high, the only thing that can do that is air or air/fuel getting into the engine. What regulates this is the throttle valve. This is the throttle valve's job. Like posted before, if the engine is idling high there is a vacuum leak or the throttle valve is not closing tight enough. Some people think a larger carb is going to dump more fuel. That's not the case. The excelerator pump is the only thing that dumps fuel and those can usually be adjusted. A larger carb tends to have a larger excelerator pump and that may need adjusting for a smaller engine. But once the throttle is pushed down, there is no more excelerator pump action. A larger carb will actually tend to run lean on a smaller engine because its all about the venturi suck or signal. Fuel is sucked out of the fuel bowl by the suction of the air flowing through the venturi, creating a vacuum. A larger carb has a larger venturi so it doesn't create a restriction as much to air flow, hence more performance. But the downfall is the suck signal is lower with a smaller engine so that the fuel mixture quality is not as good and can be lagging. Generaly we cover that up with a larger excelerator pump. There is also the power valve as rbohm talked about. Its purpose is to richen the fuel mixture when you open the throttle all the way up, hence the name power valve. It generally opens and richens the fuel mixture at a certain vacuum rating. That also will need to adjusted. High overlap cams will definintly affect the power valve operation. There's no way of really knowing if the carb will be rich or lean, there are many variables that can change the way the engine behaves (headers, etc.). Its just needs to be jetted correctly for the application. Mustang Six spoke about how a carb works much more eloquently. Maybe a search would turn up something good to read.