351c 2v 4 bbl intake options

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Zach

Well-known member
Joined
Jul 7, 2023
Messages
99
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Location
Minnesota
My Car
1971 Mustang Mach 1 351c 4 speed
Howdy, trying to plan out the mustang build in advance so I have it all ready. It’s originally an m code car but previous owner blew it up, seems they replaced it with a 71 or 72 h code setup, 2v heads, 2 bbl manifold. I have a Holley sniper kit and hyperspark setup waiting to be put in just curious what 4bbl manifolds y’all recommend that can bolt onto the 2v heads. Just going for a basic street setup, some time in the future ill get the block and heads fully worked when we wanna throw money at it. Thanks.
 
My 1972 351 H Code is equipped with an Edelbrock Performer 351-2V dual plane intake, topped with a Holley 4160 600cfm carburetor. Engine itself is stock. It generates 202 DIN horsepower and close to 450 Nm torque. Not a high revving engine but enough torque to have fun. Ignition is stock but updated with a Pertronix Ignitor 1.
Cheers Frank
 
Seems from my research the performer is a better selection for our use case, air gap seems to be more track orientated. Edelbrock has a million different buzz words makes it a bit confusing.

Appreciate the responses.
 
My H code car had a single plane holley dominator intake when i got it. I assume it was installed back in the day when there was less information for average joe hotrodders. They all thought single plane was the way to go cause thats what drag racers had.

These days, everybody has access to decades of crowd sourced information. Dual plane make more power in the RPM range where street cars spend most of their time.

When I did the rebuild, I put an edelbrock performer on it. There isn't a ton of difference in the performance between the couple of edelbrock dual plane options for the cleveland. The "lower" tier one does look a little bit more stock.
 
Sniper throws a bit of an adjustment into the mix. From what I've read, they will need an open spacer (or modified plenum) or a single plane intake to function properly.
 
The Edelbrock RPM Air-Gap manifold has good reviews.
I have the RPM AIR GAP, while I like it, I must give the warning of it is quite a bit taller than the performer. If you have a flat hood be ready to have a fun time finding the right drop base for your filter. Which won't fit when you swap over to the sniper most likely. EFI throttle bodies with built in fuel injectors are a bit fatter than a carb. Going through this now as I prepare to put on an Aces Killshot EFI. I changed to NACA hood and now have a bit more clearance. Basically if I were to do it again I would of got the performer knowing what I know now to save some headache with the clearance issues.
 
I think, therein lies the rub.......we all want to top off our engines with a "bitchin'" intake manifold. But the thing that is the elephant in the room, is, do you hack up your original hood, maybe get rid of the really cool option of the "ram air" set-up, or what? Most of us just don't want to butcher our hoods anymore, too valuable. So, if that's you, go for the intake manifold that fits best, even if you give up a bit of maximum horsepower gain. Unless you have built your engine from the block, up, with dedicated internals , including head porting and such, the maximum effort intakes won't really be using it's full potential, and in fact, often the engine makes less power than a good street manifold.
 
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Sniper throws a bit of an adjustment into the mix. From what I've read, they will need an open spacer (or modified plenum) or a single plane intake to function properly.
Seems the issue was that the vacuum was blocked off depending on the throttle bodies side. I have a sniper 2 unsure if it was an issue for the original but it has built in channels underneath it in order to have a passage way between a divorced plenum. But I will run a space if clearance allows.

I have the RPM AIR GAP, while I like it, I must give the warning of it is quite a bit taller than the performer. If you have a flat hood be ready to have a fun time finding the right drop base for your filter. Which won't fit when you swap over to the sniper most likely. EFI throttle bodies with built in fuel injectors are a bit fatter than a carb. Going through this now as I prepare to put on an Aces Killshot EFI. I changed to NACA hood and now have a bit more clearance. Basically if I were to do it again I would have got the performer knowing what I know now to save some headache with the clearance issues.
Yep seems like the performer is the more drop in factory replacement compared to the air gap. I do have a NACA hood, just no ram air or factory air cleaner.

I think, therein lies the rub.......we all want to top off our engines with a "bitchin'" intake manifold. But the thing that is the elephant in the room, is, do I hack up my original hood, maybe get rid of the really cool option of the "ram air" set-up, or what? Most of us just don't want to butcher our hoods anymore, too valuable. So, if that's you, go for the intake manifold that fits best, even if you give up maximum horsepower gain. Unless you have built your engine from the block, up, with dedicated internals , including head porting and such, the maximum effort intakes won't really be using it's potential, and in fact, often the engine makes less power than a good street manifold.
Yeah no way I’ll hack up the hood, especially a NACA one. A aluminum intake looks pretty decent no matter the shape so it’s fine by me. I’m also just trying to get in on the road give the block and heads a small refresh. Eventually we will go for a 408 stroker or something crazier than a fresh up but I just want to get it driving first.

Thanks y’all, seems performer is gonna be the pick unless someone else throws another into the pot.
 
Seems the issue was that the vacuum was blocked off depending on the throttle bodies side. I have a sniper 2 unsure if it was an issue for the original but it has built in channels underneath it in order to have a passage way between a divorced plenum. But I will run a space if clearance allows.


Yep seems like the performer is the more drop in factory replacement compared to the air gap. I do have a NACA hood, just no ram air or factory air cleaner.


Yeah no way I’ll hack up the hood, especially a NACA one. A aluminum intake looks pretty decent no matter the shape so it’s fine by me. I’m also just trying to get in on the road give the block and heads a small refresh. Eventually we will go for a 408 stroker or something crazier than a fresh up but I just want to get it driving first.

Thanks y’all, seems performer is gonna be the pick unless someone else throws another into the pot.
If you have a NACA hood already, without the ram air, you can use the RPM AIR GAP with a flat base and a 14*2 filter or a Edelbrock pro flo https://www.summitracing.com/parts/edl-1002 if you like the triangular shape with foam filter. I actually just test fit this setup for my EFI conversion. So the option is there. With my previous flat hood only a all-star drop base https://www.summitracing.com/parts/aaf-all25941 gave me enough room for a 14x3 filter. The performer is the easier route though I personally like the look of the air gap more.
 
If you have a NACA hood already, without the ram air, you can use the RPM AIR GAP with a flat base and a 14*2 filter or a Edelbrock pro flo https://www.summitracing.com/parts/edl-1002 if you like the triangular shape with foam filter. I actually just test fit this setup for my EFI conversion. So the option is there. With my previous flat hood only a all-star drop base https://www.summitracing.com/parts/aaf-all25941 gave me enough room for a 14x3 filter. The performer is the easier route though I personally like the look of the air gap more.
hmm this is some good info, it may be persuading me to the air gap. I take it you are just able to squeeze this in under the hood. Thanks I’ll keep this in mind.
 
hmm this is some good info, it may be persuading me to the air gap. I take it you are just able to squeeze this in under the hood. Thanks I’ll keep this in mind.
Yes both the Edelbrock pro flo or a flat base with 14*2 filter hood closes with no clearance issues as I could shine a light through the vent in the hood to visually check both setups. Currently have a summit 600cfm carb on the Cleveland. The Killshot is within a 1/16 of an inch in height so looks like no issue there. I would imagine the sniper would be very close in height to the Killshot. One of the many reasons I chose the Killshot over the sniper is one price, around 1100 all in with their distributor and coil for timing control. Second there ECU is standalone, not built into the throttle body so I can put it in the car away from heat, emi, and vibration. The primary killers of a computer. After I finish paint, the efi will go in. I will be sure to write up the install and review how it preforms. If you want to see that progress it will be on my build page. Plan on having it all done by summer so my wife and I can actually enjoy the car.
 
So, what I'm seeing here, is that everyone has had to toss their factory "ram air" air filter assembly, regardless of model of aftermarket intake, because all of them are too high to close the hood over.
 
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So, what I'm seeing here, is that everyone has had to toss their factory "ram air" air filter assembly, regardless of model of aftermarket intake, because all of them are too high to close the hood over.
Since half of it is built into the hood I’d imagine if the factory air cleaner base was the right height it would work, unsure though I have a NACA hood but not ram air.
 
Question about the rpm air gap, it says it works well with 4v and 2v heads does that mean the ports are 4v sized? Will that cause any issues with the smaller 2v ports in the heads?
 
So, what I'm seeing here, is that everyone has had to toss their factory "ram air" air filter assembly, regardless of model of aftermarket intake, because all of them are too high to close the hood over.
Not unless they want to toss it. I have an Edelbrock Performer 351 4V dual plane intake and a Holley 4150 with the stock Ram Air cleaner and duct work. No clearance issues on mine.
Some have the taller Blue Thunder intake and are able to retain the Ram Air, though I don't know if they had to make any modifications.
 
Question about the rpm air gap, it says it works well with 4v and 2v heads does that mean the ports are 4v sized? Will that cause any issues with the smaller 2v ports in the heads?
Actually if you read further, the air gap uses 2v size ports to increase intake velocity.
 
Sheriff.....that's what I thought. When I first bought my car, it had an Edelbrock intake and four barrel, and had all of the ram air system . It was kinda freakin me out that lots of people seemed to be talking about clearance problems, and I don't really remember having any issues. I had a 4160 style Holley which fit the air filter can as well. I've been running the factory 2v carb and intake for 20 years now, but when my new engine build goes in, the Edelbrock and 4160 is going back on.
 
Sheriff.....that's what I thought. When I first bought my car, it had an Edelbrock intake and four barrel, and had all of the ram air system . It was kinda freakin me out that lots of people seemed to be talking about clearance problems, and I don't really remember having any issues. I had a 4160 style Holley which fit the air filter can as well. I've been running the factory 2v carb and intake for 20 years now, but when my new engine build goes in, the Edelbrock and 4160 is going back on.
Difference between a performer intake and an rpm air gal intake is about an inch and a half, can add up quick. All depends I guess. I am not fortunate enough to have a ram air so I don’t have to worry about it anyways just gotta make sure I don’t hit my hood lol.
 
I run the Edelbrock airgap along with a MSD Atomic set up. I do not have ram air on my car but I do have to run a drop base for the air cleaner with a short filter. I also have AFD heads which are a raised port head making my intake about a 1/4-1/2 inch higher than stock heads. Its close but no clearance issues.
 

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