Carburetors - Gary's Musings

[Edward Michael]

Edward - Is that to me? My 750 CFM Eddy is working great. No problems with it at all.

But that's on a non-stock 460. What engine do you have? (Hint: If you'd put that info in your signature we wouldn't have to ask.) A 600 to 650 CFM carb is a better choice for a 351, if that's what you have.

Yes sir.

Stock 460 with CA smog equipment.

Open to adding an intake for better performance. Am not sure how important it is or worth the cost as

this is a working daily driver.

May EFI is the way to go for maintenance issues as we don't have any fuel without ethanol as far as I know.

Updated signature...I think.

What is a ...

Dual plate intake?

Also, not able to cut and paste in this forum. Is that normal?

Thank you and Best Regards.

[Gary Lewis]

Yes sir.

Stock 460 with CA smog equipment.

Open to adding an intake for better performance. Am not sure how important it is or worth the cost as

this is a working daily driver.

May EFI is the way to go for maintenance issues as we don't have any fuel without ethanol as far as I know.

Updated signature...I think.

What is a ...

Dual plate intake?

Also, not able to cut and paste in this forum. Is that normal?

Thank you and Best Regards.

I cut and paste all the time, so not being able to isn’t normal. And, I see the sig - thanks.

A dual-plane intake has runners that are on two different planes, and that is done to equalize the length of the runner so each cylinder’s runners are approximately the same length. And those runners tend to be longer and smaller, so that is good for low-end torque.

A single-plane intake just gets from the carb to the valve in the fastest way possible, and usually doesn’t worry about balancing lengths. So they tend to be for higher RPM and give up the low-end torque.

As for changing manifolds and carb, do you have emissions inspections? If so, won’t the changes cause problems?

As for EFI, it does help make an engine run better in all conditions, but then there’s the question of emissions testing again. And, EFI isn’t simple.

[Edward Michael]

I cut and paste all the time, so not being able to isn’t normal. And, I see the sig - thanks.

A dual-plane intake has runners that are on two different planes, and that is done to equalize the length of the runner so each cylinder’s runners are approximately the same length. And those runners tend to be longer and smaller, so that is good for low-end torque.

A single-plane intake just gets from the carb to the valve in the fastest way possible, and usually doesn’t worry about balancing lengths. So they tend to be for higher RPM and give up the low-end torque.

As for changing manifolds and carb, do you have emissions inspections? If so, won’t the changes cause problems?

As for EFI, it does help make an engine run better in all conditions, but then there’s the question of emissions testing again. And, EFI isn’t simple.

Thank you for the intake info.

We do have emissions inspections. Visual and exhaust check.

Smog said we can update the carb to new. We did not ask about a manifold and are willing to should it prove to be a worthy upgrade.

We have been through a factory remanufactured 4 barrel Holley from Summit. It failed smog due to a vacuum leak from the throttle body seal of carb. Mechanic advised it may take a few carbs before receiving one with a good throttle body seal. Also, said we can put a new carb on. The factory carb is 600cfm.

A friend had no problem smogging a mild cam, 750cfm, 460 here in California.

I understand this is too much for my stock engine now. Thank you. Planning on the 625cfm described earlier in this thread. Unless someone advises another direction.

EFI seems like it will correct the hot fuel system and that is attractive. Not simple is not attractive.

I do live in the mountains, tow a 24' trailer and it is in the 90 degree range often. Currently redoing the

fuel system and doing my best to ensure there is NO HFS problems.

There must be a smooth performing HFS solution or trouble shooting guide from the factory. Or a skilled mechanical expert on those systems. So many are on the road or have been.

[Edward Michael]

I cut and paste all the time, so not being able to isn’t normal. And, I see the sig - thanks.

A dual-plane intake has runners that are on two different planes, and that is done to equalize the length of the runner so each cylinder’s runners are approximately the same length. And those runners tend to be longer and smaller, so that is good for low-end torque.

A single-plane intake just gets from the carb to the valve in the fastest way possible, and usually doesn’t worry about balancing lengths. So they tend to be for higher RPM and give up the low-end torque.

As for changing manifolds and carb, do you have emissions inspections? If so, won’t the changes cause problems?

As for EFI, it does help make an engine run better in all conditions, but then there’s the question of emissions testing again. And, EFI isn’t simple.

Looking at the 1901 on Summit Racing site, it seems the fuel inlet is on the back of the engine.

Anyone install this carb or similar setup for stock 460 with Hot Fuel System?

Seems like the fuel line will be even warmer running along the firewall.

Is it ok to run rubber fuel line? Better to have new steel lines made?

 

[Gary Lewis]

Looking at the 1901 on Summit Racing site, it seems the fuel inlet is on the back of the engine.

Anyone install this carb or similar setup for stock 460 with Hot Fuel System?

Seems like the fuel line will be even warmer running along the firewall.

Is it ok to run rubber fuel line? Better to have new steel lines made?

I have the big brother to the 1901, the 750 CFM Street Demon, on Dad’s engine. I haven’t installed the engine in the truck yet so don’t have real-world experience with the carb. (In fact, I’m going EFI on the engine, which is one reason I can speak to the complexity of EFI.)

But Tim Meyer ran the engine with that carb on the dyno, and then swapped to a 750 CFM Holley for testing. He said that the Holley put out slightly more power at WOT, but he was pleased with the Street Demon and thought it might have had more part-throttle power and better economy. Since I don’t run WOT very often I’m not worried about a slight loss in power, and I like the design of the Street Demon.

Speaking of design, in theory there aren’t huge problems with over-carbing an engine if you use a carb with a vacuum or velocity-operated secondary. Those secondaries shouldn’t open until the engine needs the extra flow, and even then should do so smoothly. Yes, a larger carb usually has large primaries so you lose some part-throttle response, but the Street Demon’s primaries are very small so that isn’t an issue.

However, if you do go with a large carb then I would recommend a carb that has easily-adjustable secondary opening points. That eliminates the Carter AFB/Edelbrock Performer carbs as changing the opening point requires full disassembly of the carb and welding weight to or grinding weight off of an arm. Instead, in the Edelbrock line go with the Thunder series, which has an easily-adjustable secondary opening. But, the Street Demon also has that feature. 👍

[Gary Lewis]

Looking at the 1901 on Summit Racing site, it seems the fuel inlet is on the back of the engine.

Anyone install this carb or similar setup for stock 460 with Hot Fuel System?

Seems like the fuel line will be even warmer running along the firewall.

Is it ok to run rubber fuel line? Better to have new steel lines made?

Oops, I missed the bit about hot fuel. The factory system works with the Holley, but I’m not sure about using it with an Edelbrock, which doesn’t like more than 6 psi of fuel pressure. So I’m running a dead-head style regulator on Big Blue to ensure that the pressure is below 6.

But, when I pull the engine to seal up the leaks I’m going to replace the hot-fuel system with a return-style regulator and remove the factory hot-fuel system. That will return some fuel to keep it cool and will keep the pressure down - all in one device.

As for rubber lines, yes they work. I’m running the newer ethanol-resistant hose in Big Blue’s fuel system with no problem. But I’m thinking of shielding the lines from heat with a sleeve made for that purpose. That’s because the black hose will absorb more heat from the engine than shiny steel line will. However, it also insulated to some extent, although I don’t know how much. So, I’ll use the sleeve for insurance.

[ArdWrknTrk]

Oops, I missed the bit about hot fuel. The factory system works with the Holley, but I’m not sure about using it with an Edelbrock, which doesn’t like more than 6 psi of fuel pressure. So I’m running a dead-head style regulator on Big Blue to ensure that the pressure is below 6.

But, when I pull the engine to seal up the leaks I’m going to replace the hot-fuel system with a return-style regulator and remove the factory hot-fuel system. That will return some fuel to keep it cool and will keep the pressure down - all in one device.

As for rubber lines, yes they work. I’m running the newer ethanol-resistant hose in Big Blue’s fuel system with no problem. But I’m thinking of shielding the lines from heat with a sleeve made for that purpose. That’s because the black hose will absorb more heat from the engine than shiny steel line will. However, it also insulated to some extent, although I don’t know how much. So, I’ll use the sleeve for insurance.

My 650 Thunder will be up for sale soon.

For the Holley you can get the quick change spring kit, so you don't have to take everything apart.

[Gary Lewis]

My 650 Thunder will be up for sale soon.

For the Holley you can get the quick change spring kit, so you don't have to take everything apart.

Jim - Your 650 is currently set up for a 460, right?

[Edward Michael]

Oops, I missed the bit about hot fuel. The factory system works with the Holley, but I’m not sure about using it with an Edelbrock, which doesn’t like more than 6 psi of fuel pressure. So I’m running a dead-head style regulator on Big Blue to ensure that the pressure is below 6.

But, when I pull the engine to seal up the leaks I’m going to replace the hot-fuel system with a return-style regulator and remove the factory hot-fuel system. That will return some fuel to keep it cool and will keep the pressure down - all in one device.

As for rubber lines, yes they work. I’m running the newer ethanol-resistant hose in Big Blue’s fuel system with no problem. But I’m thinking of shielding the lines from heat with a sleeve made for that purpose. That’s because the black hose will absorb more heat from the engine than shiny steel line will. However, it also insulated to some extent, although I don’t know how much. So, I’ll use the sleeve for insurance.

Thank you Gary.

Did some reading on fuel line and interested in your research and choice of ethanol resistant fuel line and

heat shield.

Next to research the dead-head style regulator and interested in your part choice.

Very interested in the return-style regulator part choice and HFS removal as the thought did come up that there may be a better design than was available in the 80's. It's possible!-)

Also sitting with carb choice...

Not sure about the fuel line route on the firewall. That alone stopped me from ordering the eddy today.

 

[Gary Lewis]

Thank you Gary.

Did some reading on fuel line and interested in your research and choice of ethanol resistant fuel line and

heat shield.

Next to research the dead-head style regulator and interested in your part choice.

Very interested in the return-style regulator part choice and HFS removal as the thought did come up that there may be a better design than was available in the 80's. It's possible!-)

Also sitting with carb choice...

Not sure about the fuel line route on the firewall. That alone stopped me from ordering the eddy today.

Here are some ideas on the heat shield:

• https://www.amazon.com/Heat-Shielded-Sleeve-Lines-Electrical-Wiring/dp/B015S65VJ0/ref=sr_1_9?s=automotive&ie=UTF8&qid=1486428652&sr=1-9&keywords=fuel+line+insulation

• https://www.amazon.com/Heatshield-Products-204011-Sleeve-Roll/dp/B00FS6CIA6/ref=sr_1_1?s=automotive&ie=UTF8&qid=1486428652&sr=1-1&keywords=fuel+line+insulation

• https://www.amazon.com/010403-0-75-Aluminized-Sleeving-Sheath/dp/B000E267M4/ref=sr_1_2?s=automotive&ie=UTF8&qid=1486428652&sr=1-2&keywords=fuel+line+insulation

And here’s the return-style fuel pressure regulator I’m going to use: https://www.holley.com/products/fuel_systems/fuel_pumps_regulators_and_filters/regulators/carbureted_regulators/parts/12-803BP. Ford’s hot-fuel handling system is just an orifice that allows any vapor that builds up to escape back to the tank. Or, a very small amount of fuel. But it doesn’t regulate the pressure at all. This one will.

Don’t miss that Jim is selling his Thunder Series carb. He has it on his 460 so it should bolt right on yours.