Edelbrock Performer RPM

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rebelcaptain

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I am the original owner of a 71 340 Duster, 4-speed. The car is street driven with just over 50k miles.
Currently, I have a Edelbrock LD340 manifold with a Quick Fuel carb.
What do you think the benefits of replacing the LD340 with a Performer RPM.
I am quite sure I'd have to find a bit lower air cleaned for hood clearance.
 
Is your motor all stock internally?

I'm not up to date on the LD340, but wasn't their a small port window version?
 
No that I'm aware of Dano.

Rebel Capt. On the dyno, you'll find more power. At the track, you'll be hard pressed to justify the money spent on the minimal gain.
By way of the seat of the pants feel, you'll never know the difference.

The RPM has a smaller port window with better runners. This will aid in the "Off the line performance."
The LD-340 has a large port window that can move a lot of air. But the runners are not so smooth. This intake has a lot of potential behind it.
 
rebelcaptain said:
I am the original owner of a 71 340 Duster, 4-speed. The car is street driven with just over 50k miles.
Currently, I have a Edelbrock LD340 manifold with a Quick Fuel carb.
What do you think the benefits of replacing the LD340 with a Performer RPM.
I am quite sure I'd have to find a bit lower air cleaned for hood clearance.
Click to expand...

The performer RPM is a great intake, the best all around intake. You see an improve across the spectrum.

Your QF carb, the RPM intake and stock air cleaner will fit. Keep the hold down stud to the minimum length though. It will be a tight fit with the stock hood.
 
Both are great intakes, but it will be a waste of intake gaskets to change it, you will never know the difference on the street.
 
I have a friend who runs a 340 Demon in the Sportsman classes (Stock and Super Stock). He advised me not to spend money on buying the Performer RPM since I already had the LD340. He told me to smoothen the plenum and runners and since my plenum divider had the small notch already cut into it that was all I needed to do short of gasket matching the ports.
 
replicaracer43 said:
Both are great intakes, but it will be a waste of intake gaskets to change it, you will never know the difference on the street.
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DFX 340 Duster said:
I have a friend who runs a 340 Demon in the Sportsman classes (Stock and Super Stock). He advised me not to spend money on buying the Performer RPM since I already had the LD340. He told me to smoothen the plenum and runners and since my plenum divider had the small notch already cut into it that was all I needed to do short of gasket matching the ports.
Click to expand...

Spot on advice.

I would not mess with the divider if it's still in place. It's a decent mod for an engine that will run at high RPM all the time, will cost down low on the street.

I run LD340's with a 1" open spacer on them. Hard combo to beat for a hotter street car.
 
Yes, guys; my 340 is mostly stock. Bored .30 with new pistons and rods 25 years ago [maybe 5,00 miles :) ] Car has 52k miles on it
 
The LD340, RPM and Air Gap are so similar, that if you have one of them already, it's a waste of gaskets/time to swap to another in that group of three.

Only reason I would do a swap is if I wanted a period correct 70's style and swapping to a LD340. Other than that, run what you have would be my suggestion.
 
Yea man! What he said.

The air gap is nice and worth a few more ponies over a regular rpm due to the lack of heat but also keep in mind that the intake will have your car throwing fits in the cold with the choke constantly coming back on and long periods of warm up.

If it is a warm weather car onky, no worries.
The LD-340 is capable. The large runners move a lot of air.
 
rumblefish360 said:
The air gap is nice and worth a few more ponies over a regular rpm due to the lack of heat but also keep in mind that the intake will have your car throwing fits in the cold with the choke constantly coming back on and long periods of warm up.
Click to expand...

If your car is doing this to you something is wrong.

Mine doesn't have a choke and this isn't an issue.
 
rumblefish360 said:
Yea man! What he said.

The air gap is nice and worth a few more ponies over a regular rpm due to the lack of heat but also keep in mind that the intake will have your car throwing fits in the cold with the choke constantly coming back on and long periods of warm up.

If it is a warm weather car onky, no worries.
The LD-340 is capable. The large runners move a lot of air.
Click to expand...

roccodart440 said:
If your car is doing this to you something is wrong.

Mine doesn't have a choke and this isn't an issue.
Click to expand...

I agree with rocco on this one. I know "New York cold" and "California cold" are pretty different, don't get me wrong. But I have plenty of below freezing starts on the Eddy air gap on my my 340, never had any issues with it. It fires immediately on the first crank, dies before the electric choke kicks in, and runs 99.9% of the time right off the 2nd crank. That's with a street avenger carb with an electric choke.

But yeah, I'm talking less than 32*F and usually more than about 28*F, it usually isn't colder than that here when I'm trying to go to work. So, if you're talking less than 28*F, my comments may not apply.
 
I would leave it on there man. especially if its close to stock. The smaller port version of that ld340 is the ld4b.
 
roccodart440 said:
If your car is doing this to you something is wrong.

Mine doesn't have a choke and this isn't an issue.
Click to expand...

First up! If my car is doing this then Something is right. Here's why.
(I can't beileve I'm about to explain to you this)

Let's see... The choke comes on because it's cold right?
OK, chokes on and you start the car and it runs.
Then the car ingestes cold air be it by cold air through the carb or across the outside of the carb, the spring feels the cold air and then moves closing the choke.


What did you miss Rocco?
What do you think I missed?

2nd Your engine doesn't have a choke and it works fine.
Freakin great!

How does that dream carb of yours work? I've run chokless carbs before so do not tells it runs perfect all the time. Or do you rejet it for warmer months?

Please re-school us all on how an electric choke works!
I'm dieing to know! It's been a 30 year mystery!
Please tell me how on MY CAR SET UP, it's wrong.
Considering you have never seen my car, this is a trick David Copperfeild couldn't pull off.
 
72bluNblu said:
I agree with rocco on this one. I know "New York cold" and "California cold" are pretty different, don't get me wrong. But I have plenty of below freezing starts on the Eddy air gap on my my 340, never had any issues with it. It fires immediately on the first crank, dies before the electric choke kicks in, and runs 99.9% of the time right off the 2nd crank. That's with a street avenger carb with an electric choke.

But yeah, I'm talking less than 32*F and usually more than about 28*F, it usually isn't colder than that here when I'm trying to go to work. So, if you're talking less than 28*F, my comments may not apply.
Click to expand...

Do you have the carb sealed away from cold air from outside?
How long is warm up? (Ball park will do.)
Is the car fully warmed up to operating temps with hot air blowing inside the cabin?

You say it dies before the electric choke kicks in? At the risk of sounding stupid and/or insultive, do you pump the gas pedal once before you start it to set the choke?

And yes, I did say cold. Operating temps still come (relatively) quick even at 32*'s. I only consider 32*'s cold when the summer ends and it dips down there quickly. At 32*'s it is possible to find me fixing cars on my concrete garage floor.
 
rumblefish360 said:
Do you have the carb sealed away from cold air from outside?
Click to expand...

Nope. Car's outside, standard mopar performance air cleaner, functional factory style hood scoops.

rumblefish360 said:
How long is warm up? (Ball park will do.)
Click to expand...

Between 5-10 minutes usually if it's near freezing. About as long as I need to scrape the ice off. That gets me to 160*, so I'm not worried about the valvetrain at that point and I start driving. The engine acts a little cold blooded for the first half mile, likes it better if I keep the idle a little higher with the peddle at stops signs. After that it's great.

rumblefish360 said:
Is the car fully warmed up to operating temps with hot air blowing inside the cabin?
Click to expand...

Ish. 5-10 minutes gets me to 160*, I usually have completely hot air once I get to 180* which is another few minutes down the road. Thermostat is a 180*. When it's that cold the thermostat opens and closes as I'm driving because of the 3 core 26" aluminum radiator, and my electric fans never come on. I've actually given some thought to a partial radiator cover like the tractor/trailer guys run. But yeah, it's California so I don't need it enough that I actually came up with something.


rumblefish360 said:
You say it dies before the electric choke kicks in? At the risk of sounding stupid and/or insultive, do you pump the gas pedal once before you start it to set the choke?
Click to expand...

Yeah I'm not the guy to explain how an electric choke actually works, other than I've been happier with the Holley electric chokes than I have been with anything else, including manual. I pump the pedal twice which activates the choke and high idle, the engine cranks and fires immediately, dies just as immediately, and runs fine on restart. It usually only does that when its below 50*. Above that it fires, then the RPM's drop for a second, then go back up to high idle. My assumption is that it has something to do with how the electric choke actually gets power through the start/run circuit.

rumblefish360 said:
And yes, I did say cold. Operating temps still come (relatively) quick even at 32*'s. I only consider 32*'s cold when the summer ends and it dips down there quickly. At 32*'s it is possible to find me fixing cars on my concrete garage floor.
Click to expand...

Oh I know I'm pretty spoiled when it comes to temperatures. Where I'm at now usually doesn't see a whole lot of mornings that start much below 30* when I'm firing off the car to drive to work.
 
OK! That last paragraph just killed me inside.
I (almost) can't wait to retire south! I work outdoors at nights. Yea, winters are getting to me a little quicker than in the past.
 
I would leave the LD340 on, it is a great manifold.

As far as cold winter starts, my guess this sits in a garage, and is a pretty pampered car, since he bought it new 44 years ago and it only has 50K miles.

Please post a picture of your car.
 
rumblefish360 said:
The air gap is nice and worth a few more ponies over a regular rpm due to the lack of heat but also keep in mind that the intake will have your car throwing fits in the cold with the choke constantly coming back on and long periods of warm up.

/QUOTE]


rumblefish360 said:
If my car is doing this then Something is right. Here's why.
(I can't beileve I'm about to explain to you this)

Let's see... The choke comes on because it's cold right?
OK, chokes on and you start the car and it runs.
Then the car ingestes cold air be it by cold air through the carb or across the outside of the carb, the spring feels the cold air and then moves closing the choke.


What did you miss Rocco?
What do you think I missed?

2nd Your engine doesn't have a choke and it works fine.
Freakin great!

How does that dream carb of yours work? I've run chokless carbs before so do not tells it runs perfect all the time. Or do you rejet it for warmer months?

Please re-school us all on how an electric choke works!
I'm dieing to know! It's been a 30 year mystery!
Please tell me how on MY CAR SET UP, it's wrong.
Considering you have never seen my car, this is a trick David Copperfeild couldn't pull off.
Click to expand...

I know how a choke works..

If you car is throwing fits, sounds wrong to me, but hey, maybe that's the way it's supposed to be.

My carb is a 950 proform (milled airhorn). It's been dyno tuned and track tested. The A/F ratio is spot on across the spectrum. (idle to 6200) My "dream carb" works great. But that's according to me. According to you it should be throwing fits. Maybe you can come and fix it for me?
Click to expand...
 
Naaa.... If your happy with it all year long under one single tune, have at it. LOL! What ever makes you happy.

Try a daily driver with an AG from the heat of summer to the cold of winter. Let me know what you think about it. Even more so when it gets down to the teens or less. When that open air from outside hits the carb and closes the choke or even worse, freezes it up.

That AG in cold weather can work, but unt it is heat soak through and through....
Small blocks start acting like big blocks in warm up time. Add a hood scoop and that choke is going to flop on and off for you.

You'll see!

How you even bring in a chokless carb into a day driver discussion is baffling.
I have no doubt they work! For there intended purpose.
 
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