Best 351C cast iron intake

Best 351C cast iron intake

Joined: January 26th, 2011, 10:15 pm

December 16th, 2011, 1:09 am #1

Hi, which 351c 4V cast iron intake manifold makes the best power and torque on the street? I currently have the DOAE-9425-L squarebored intake, but would consider getting one of the Cobra Jet spreadbore intakes (D1ZE-9425-BB or D3ZE-9425-AA) if there's a substantial performance increase.

The carb holes in mine are 1-5/8" (1.625"). What are the CJ hole sizes?

DOAE-9425-L
http://mustangtek.com/D0AE-9425-L.html

D1ZE-9425-BB
http://mustangtek.com/Intake/D1ZE-9425-BB.html

D3ZE-9425-AA
http://mustangtek.com/Intake/D3ZE-9425-AA.html

Thank you.
Jim
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Joined: July 26th, 2002, 1:52 am

December 16th, 2011, 1:53 am #2

the others were optimized for a 4300 carb. avoid 4300's like the plague

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Joined: October 1st, 2004, 8:05 pm

December 16th, 2011, 1:55 am #3

Hi, which 351c 4V cast iron intake manifold makes the best power and torque on the street? I currently have the DOAE-9425-L squarebored intake, but would consider getting one of the Cobra Jet spreadbore intakes (D1ZE-9425-BB or D3ZE-9425-AA) if there's a substantial performance increase.

The carb holes in mine are 1-5/8" (1.625"). What are the CJ hole sizes?

DOAE-9425-L
http://mustangtek.com/D0AE-9425-L.html

D1ZE-9425-BB
http://mustangtek.com/Intake/D1ZE-9425-BB.html

D3ZE-9425-AA
http://mustangtek.com/Intake/D3ZE-9425-AA.html

Thank you.
Jim
A 600 holley is good enough for a motor that will never be revved above 5500 rpm.
Last edited by gpence on December 17th, 2011, 7:59 pm, edited 1 time in total.
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Joined: January 26th, 2011, 10:15 pm

December 16th, 2011, 5:27 am #4

I might have a lead on a 71 or 72 CJ 4V cast intake and its stock carb.

The BT looks nice, but $420 is way out of my budget.

Does the Edelbrock Performer for 4V have the same or better performance than a stock cast intakes? I suppose the performer intake ports would need port matched to the 4V heads, right?

I'm currently running a Summit Racing 750 PD that I'd like to use on the Cleveland. This carb rocks with my current combo and it's easy to tune. Too bad it wont fit the DOAE intake.

Thanks.
Jim
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Joined: October 1st, 2004, 8:05 pm

December 16th, 2011, 7:21 am #5

the Edelbrock Performer works just fine. I've never seen a comparison, but its at least on par with the oem manifolds.

The D0AE manifold will work with your carb if you use a 4 hole spacer, or you can have it brazed & machined to really fit.

-G
____________________________________________________________

Pantera Photos | 351C Historic Information | 351C Technical Information

If you use a 351C 4V powered vehicle for a grocery getter ... the eggs aren't going to make it home!
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Joined: March 9th, 2004, 3:37 pm

December 16th, 2011, 3:33 pm #6

I might have a lead on a 71 or 72 CJ 4V cast intake and its stock carb.

The BT looks nice, but $420 is way out of my budget.

Does the Edelbrock Performer for 4V have the same or better performance than a stock cast intakes? I suppose the performer intake ports would need port matched to the 4V heads, right?

I'm currently running a Summit Racing 750 PD that I'd like to use on the Cleveland. This carb rocks with my current combo and it's easy to tune. Too bad it wont fit the DOAE intake.

Thanks.
Jim
I ran a DOAE intake with a 4-hole spacer and a 700 holley without any modification for matching the spacer and the intake. The mismatch is not that bad. I dynoed the factory intake vs. a Torker. IIRC, the factory intake performed better below 4K and held on very well to 5500. With anything, it depends on your intended usage. I ended using the Torker because I have a 4-speed and 3.73s, the RPMs at WOT never really drop below 4K once you're out of 1st gear. The Torker pulled harder from 5000-6200 and that was fun for a while (charing Rhino).
In the end, I swapped the Torker for a RPM Airgap. It runs circles around the Torker (only based on butt-dyno). It has more torque everywhere below 5500, BUT because of this, it doesn't make the "charge like a Rhino" that the 4V cleve is noted for. And, it gives up at 5800-6000.
If this is a street car and the RPMs are going to stay under 5500, I would say use the DOAE because you already have it and it performs well if the rest of the combo is good.

Good luck,
James P.
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Joined: December 16th, 2003, 1:59 am

December 16th, 2011, 6:50 pm #7

the 750 bores are bigger than the intake will allow?

on a budget i'd be chamfering the intake by hand with files if necessary. a drill motor and a rotary file would be easier, then finish by hand

possible just a thick gasket would make the difference too
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Joined: March 9th, 2004, 3:37 pm

December 16th, 2011, 7:56 pm #8

While it looks like a squarebore intake the front holes are a little smaller than the back ones. Butterflies won't open all the way. 4-hole spacer makes everything OK. Seriously, not worth the effort to match them up IMHO.
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Joined: January 26th, 2011, 10:15 pm

December 17th, 2011, 5:04 pm #9

5500rpm will be my max RPM and Id only rev it that high just to get some base dyno numbers. The engine will be in a street/show car. So, Ill probably just stick with my factory intake and use a 4-hole space like you guys recommend. Right now, I have a factory 1 spacer D4TE-9A589-BB. The holes are 1-5/8. Will this work or will the hole need bored out and or just tapered? I guess Ill pull off my Summit Racing 750DP today and measure the butterflys.
Thanks
Jim
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Joined: August 11th, 2005, 2:16 pm

December 17th, 2011, 5:43 pm #10

I ran a DOAE intake with a 4-hole spacer and a 700 holley without any modification for matching the spacer and the intake. The mismatch is not that bad. I dynoed the factory intake vs. a Torker. IIRC, the factory intake performed better below 4K and held on very well to 5500. With anything, it depends on your intended usage. I ended using the Torker because I have a 4-speed and 3.73s, the RPMs at WOT never really drop below 4K once you're out of 1st gear. The Torker pulled harder from 5000-6200 and that was fun for a while (charing Rhino).
In the end, I swapped the Torker for a RPM Airgap. It runs circles around the Torker (only based on butt-dyno). It has more torque everywhere below 5500, BUT because of this, it doesn't make the "charge like a Rhino" that the 4V cleve is noted for. And, it gives up at 5800-6000.
If this is a street car and the RPMs are going to stay under 5500, I would say use the DOAE because you already have it and it performs well if the rest of the combo is good.

Good luck,
James P.
In the end, I swapped the Torker for a RPM Airgap. It runs circles around the Torker (only based on butt-dyno). It has more torque everywhere below 5500, BUT because of this, it doesn't make the "charge like a Rhino" that the 4V cleve is noted for. And, it gives up at 5800-6000.

I don't know what setup you had there but mine will hit the rev limiter (6200) easily in any gear with the RPM AirGap, and it does not surprise me at all that it out-performs the Torker. I also have an ally BuddyBar copy of the stock 4V intake and the RPM kills that too. It is a very good intake, despite what some say. HTH
Cheers, Martin
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