Another Intake Manifold question w/factory Ram Air

[Okie351]

I did a few searches but found contradicting answers -- So, I'm currently running a 351C 4V Holley Strip Dominator intake AND factory RamAir. No clearance issues. I'm wanting to try a RPM AirGap WITH RamAir.
Will the Airgap intake work with factory RamAir? Real world experience please.
Thanks !

 

[MikeGriese]

I would think there is a height spec for both manifolds.

 

[Okie351]

Here's list #1 I found.

Blue Thunder 4V 4 3/8 5 3/8

Bud Moore Maxi-Plenum 6 5/8 6 5/8

Coffield IR 9 1/2 9 1/2

Edelbrock A331 (Edelbrock) 4 5/16 5 5/16

Edelbrock A331 (Roush) 6 3/4 6 3/4

Edelbrock Performer LB 2V 3 1/2 4 3/8

Edelbrock Performer RPM Air Gap 2V 4 1/2 5 5/8

Edelbrock Torker 4V 4 1/2 5 1/2

Ford 4V aluminum dual plane 3 1/4 4 3/8

Ford Motorsport A351 (Roush) 6 3/4 6 3/4

Ford Motorsport B351 (Roush) 6 3/8 6 3/8

Ford Motorsport C351 (Edelbrock) 7 7

Holley Street Dominator 2V 4 3/8 5 3/8

Holley Strip Dominator 4V 4 1/4 5 1/4

 

[Okie351]

Here's list #2 I found.

The measurements represent the drop from a straight edge laid across the carb pad to the closest point where the end rail bends inward (each end). Measurements are in inches:

Ford aluminum 4V ---------------------- 3 1/4 --- 4 3/8
EdelbrockF-351 Performer 2V ---------- 3 1/2 --- 4 3/8
Offenhauser360 4V -------------------- 3 1/2 --- 4 1/2
WeiandXcelerator 2V ------------------ 4 3/16 -- 5 1/8
HolleyStrip Dominator ---------------- 4 5/16 -- 5 3/8
BlueThunder -------------------------- 4 7/16 -- 5 3/8
Weiandtunnel Ram --------------------- 9 1/16 -- 9 3/8
base-------------------- 6 1/4 --- 6 1/4
top--------------------- 2 3/4 --- 3 1/8
A331(Edelbrock version, not Roush) --- 4 3/8 --- 5 5/16
FordMotorsport A351 (Roush) ---------- 6 3/4 --- 6 3/4

 

[Cleveland Crush]

Here's list #2 I found.

The measurements represent the drop from a straight edge laid across the carb pad to the closest point where the end rail bends inward (each end). Measurements are in inches:

Ford aluminum 4V ---------------------- 3 1/4 --- 4 3/8
EdelbrockF-351 Performer 2V ---------- 3 1/2 --- 4 3/8
Offenhauser360 4V -------------------- 3 1/2 --- 4 1/2
WeiandXcelerator 2V ------------------ 4 3/16 -- 5 1/8
HolleyStrip Dominator ---------------- 4 5/16 -- 5 3/8
BlueThunder -------------------------- 4 7/16 -- 5 3/8
Weiandtunnel Ram --------------------- 9 1/16 -- 9 3/8
base-------------------- 6 1/4 --- 6 1/4
top--------------------- 2 3/4 --- 3 1/8
A331(Edelbrock version, not Roush) --- 4 3/8 --- 5 5/16
FordMotorsport A351 (Roush) ---------- 6 3/4 --- 6 3/4

Forum member @basstrix is developing a refined version of these intake clearance charts. Perhaps he will chime in on this.

 

[Okie351]

Forum member @basstrix is developing a refined version of these intake clearance charts. Perhaps he will chime in on this.

Thanks ! That would be Great for all of us

 

[basstrix]

Yes, what @Cleveland Crush is referring to is a project I'm working on which resulted from my search for an intake that works with AFD 4v heads and fits under the hood. I took a bunch of measurements to establish the distance of various reference points to the ceiling of a NACA/NASA hood. I don't know how any of these measures relate to a Ram Air setup, but the info is there to figure out where you're at.

I started with Dan Jones' table of intake measurements....it looks much like what's posted above. I also have some of the intakes on the list, so I measured them for comparison. For the most part, my intake measurements are very close to Mr. Jones'. There is a simplistic diagram that is intended to represent a 351c in a 72 mustang chassis. The dimensions shown on the diagram are for a 351c with iron 4v heads, Edelbrock RPM Air Gap intake, and a Holley 4150 carb. There's a 1/4" thick base gasket and a drop base air filter. I wasn't able to measure from the hood to the front and rear end seal surfaces, as is reported in Mr Jones' table, so I used the center of the carb as my reference. I also did an actual measure to the center of carb pad (which is what I was able to measure on the car) vs the average of the end seal measures. The result is shown in the table. The average value seems slightly larger than the measured value...which will produce a conservative result. I've only performed one validation test. I placed a lump of modeling clay on the air filter nut and closed the hood. The calculated value, based on measurements, was 1.125". The clay measured 1.68", but, and it's an important but, the hood is a reproduction hood is bowed upwards and isn't perfectly aligned. The last variable is the intake. The Air Gap is installed, thus I wasn't able to measure to the center of carb pad...it uses the average value from the table. The good news is that I still think the numbers are a little bit conservative.

My disclaimer is that I don't guarantee any of these numbers and use them at your own discretion.




Edit: I realized that the final column was for AFD heads, so I added a column for Iron heads. The difference is the additional 0.344" the intake is raised by the wider AFD heads.

 

[Okie351]

Yes, what @Cleveland Crush is referring to is a project I'm working on which resulted from my search for an intake that works with AFD 4v heads and fits under the hood. I took a bunch of measurements to establish the distance of various reference points to the ceiling of a NACA/NASA hood. I don't know how any of these measures relate to a Ram Air setup, but the info is there to figure out where you're at.

I started with Dan Jones' table of intake measurements....it looks much like what's posted above. I also have some of the intakes on the list, so I measured them for comparison. For the most part, my intake measurements are very close to Mr. Jones'. There is a simplistic diagram that is intended to represent a 351c in a 72 mustang chassis. The dimensions shown on the diagram are for a 351c with iron 4v heads, Edelbrock RPM Air Gap intake, and a Holley 4150 carb. There's a 1/4" thick base gasket and a drop base air filter. I wasn't able to measure from the hood to the front and rear end seal surfaces, as is reported in Mr Jones' table, so I used the center of the carb as my reference. I also did an actual measure to the center of carb pad (which is what I was able to measure on the car) vs the average of the end seal measures. The result is shown in the table. The average value seems slightly larger than the measured value...which will produce a conservative result. I've only performed one validation test. I placed a lump of modeling clay on the air filter nut and closed the hood. The calculated value, based on measurements, was 1.125". The clay measured 1.68", but, and it's an important but, the hood is a reproduction hood is bowed upwards and isn't perfectly aligned. The last variable is the intake. The Air Gap is installed, thus I wasn't able to measure to the center of carb pad...it uses the average value from the table. The good news is that I still think the numbers are a little bit conservative.

My disclaimer is that I don't guarantee any of these numbers and use them at your own discretion.

View attachment 97808
View attachment 97809

Thank You for your Work and Efforts for us !

 

[boilermaster]

Okie351,
Would love to see port sizes of all these intakes as well.
Boilermaster

 

[70cobrascj]

Yes, what @Cleveland Crush is referring to is a project I'm working on which resulted from my search for an intake that works with AFD 4v heads and fits under the hood. I took a bunch of measurements to establish the distance of various reference points to the ceiling of a NACA/NASA hood. I don't know how any of these measures relate to a Ram Air setup, but the info is there to figure out where you're at.

I started with Dan Jones' table of intake measurements....it looks much like what's posted above. I also have some of the intakes on the list, so I measured them for comparison. For the most part, my intake measurements are very close to Mr. Jones'. There is a simplistic diagram that is intended to represent a 351c in a 72 mustang chassis. The dimensions shown on the diagram are for a 351c with iron 4v heads, Edelbrock RPM Air Gap intake, and a Holley 4150 carb. There's a 1/4" thick base gasket and a drop base air filter. I wasn't able to measure from the hood to the front and rear end seal surfaces, as is reported in Mr Jones' table, so I used the center of the carb as my reference. I also did an actual measure to the center of carb pad (which is what I was able to measure on the car) vs the average of the end seal measures. The result is shown in the table. The average value seems slightly larger than the measured value...which will produce a conservative result. I've only performed one validation test. I placed a lump of modeling clay on the air filter nut and closed the hood. The calculated value, based on measurements, was 1.125". The clay measured 1.68", but, and it's an important but, the hood is a reproduction hood is bowed upwards and isn't perfectly aligned. The last variable is the intake. The Air Gap is installed, thus I wasn't able to measure to the center of carb pad...it uses the average value from the table. The good news is that I still think the numbers are a little bit conservative.

My disclaimer is that I don't guarantee any of these numbers and use them at your own discretion.

View attachment 97808
View attachment 97809

No info on the Trick Flow intake?

 

[boilermaster]

70cobrascj,
TFS 51600111 is listed @ 6.370'' (@ center of pad?)
port size is 1.500'' x 2.100''

 

[tony-muscle]

Yes, what @Cleveland Crush is referring to is a project I'm working on which resulted from my search for an intake that works with AFD 4v heads and fits under the hood. I took a bunch of measurements to establish the distance of various reference points to the ceiling of a NACA/NASA hood. I don't know how any of these measures relate to a Ram Air setup, but the info is there to figure out where you're at.

I started with Dan Jones' table of intake measurements....it looks much like what's posted above. I also have some of the intakes on the list, so I measured them for comparison. For the most part, my intake measurements are very close to Mr. Jones'. There is a simplistic diagram that is intended to represent a 351c in a 72 mustang chassis. The dimensions shown on the diagram are for a 351c with iron 4v heads, Edelbrock RPM Air Gap intake, and a Holley 4150 carb. There's a 1/4" thick base gasket and a drop base air filter. I wasn't able to measure from the hood to the front and rear end seal surfaces, as is reported in Mr Jones' table, so I used the center of the carb as my reference. I also did an actual measure to the center of carb pad (which is what I was able to measure on the car) vs the average of the end seal measures. The result is shown in the table. The average value seems slightly larger than the measured value...which will produce a conservative result. I've only performed one validation test. I placed a lump of modeling clay on the air filter nut and closed the hood. The calculated value, based on measurements, was 1.125". The clay measured 1.68", but, and it's an important but, the hood is a reproduction hood is bowed upwards and isn't perfectly aligned. The last variable is the intake. The Air Gap is installed, thus I wasn't able to measure to the center of carb pad...it uses the average value from the table. The good news is that I still think the numbers are a little bit conservative.

My disclaimer is that I don't guarantee any of these numbers and use them at your own discretion.

Excellent work and thank you for sharing this. On the table, is "ceiling" considered the hood?

 

[basstrix]

Excellent work and thank you for sharing this. On the table, is "ceiling" considered the hood?

Ceiling is the underside of the hood directly above the center of carb.

 

[tony-muscle]

Ceiling is the underside of the hood directly above the center of carb.

I will try to add some relative RAM air plenum measurements to help future readers.