Street intake manifold for iron cj heads,suggestions, thoughts?

I have a 466CI w/iron cj heads. Street car with .233/.241 @ .050 flat tappet cam, 850 cfm, 4 spd, 3.5 gear.

I am considering the 8021 CJ stealth or the Torker II with a 1" power cone. I am looking for the best power from 2000 up. The stealth has the right port size, the torker and most others have a much smaller port exit. My question is which one would work best with the oversized cj ports, and would there be a noticeable difference between the two?



Thanks

RPM is what I have now. I can't get it to seal, it sucks oil from the valley. I set the manifold on the heads with shims at each corner and it seems bowed just over .100" in the center. I set the manifold on the heads with no shims or gaskets and it rocks back and forth, so not sitting flat.

That's my thought. Since I need another manifold, this is why I am asking for suggestions.

The iron cj ports are so big, I was wondering which manifold would help or hinder the velocity, or would there be enough difference to notice on a street car.

I agree, the performer RPM works well. I think mine was warped when I got the car cause it always used a little oil. I thought it was probably guides/seals until I tore the engine down. For whatever reason, it is worse now then it was before.

Why not just have the manifold surfaced?
And you must mean .010", not .100".

I did mean .100".

69BOSS wrote:I have a 466CI w/iron cj heads. Street car with .233/.241 @ .050 flat tappet cam, 850 cfm, 4 spd, 3.5 gear.

I am considering the 8021 CJ stealth or the Torker II with a 1" power cone. I am looking for the best power from 2000 up. The stealth has the right port size, the torker and most others have a much smaller port exit. My question is which one would work best with the oversized cj ports, and would there be a noticeable difference between the two?

Thanks

If power is the main goal here, I would use a Torquer II and port match runners 1,3,6,8 only. Porting the others won't help performance and only increase port volume, which you don't need.

Power is what it's all about. there is shortage of torque so I want it pull the best it can to redline.
Is there enough meat to open those up to cj port size, and how far up the runner should I go? Also, is a 1" spacer worthwhile?

69BOSS wrote:Power is what it's all about. there is shortage of torque so I want it pull the best it can to redline.
Is there enough meat to open those up to cj port size, and how far up the runner should I go? Also, is a 1" spacer worthwhile?

YES, there is enough metal there if you "PORT" match those ports, NOT "gasket" match it

Blend them about 2 to 2 1/2 inches up-into those ports.

Just curious, why those specific cylinders, is it something to do with the runner design? Do you have a CNC program for this manifold?

If you want the higher RPM power, then I would think that the Weiand Stealth would be better, no??

I am not which is best for my combination. Sounds like the response from RMComp knows what he is talking about.

stealth

What I've done with both the RPM intakes as well as the T2 is to raise the port roof to near runner entry height on the cylinder head castings being used.
On smaller engines like RM noted 1 3 6 and 8 due to the runner airflow relationship with the intake ports for those cylinders.

On larger engines All runner exits to CJ height and on the T2 a power cone spacer.

When flow testing both the RPM intake and ported SCJ's (375 ish cfm @ .600") as a unit raising the runner exits to near entry height showed a gain from 295 cfm as cast up to 325 to 335 per runner. CJ intake ports like the flow bias at the roof more so than at the center of the port. I biased 1 3 6 and 8 to the left side of the intake runner and left the others as cast so far as runner exit width. The low runners on the dual plane RPM flowed better on cylinder head than the high runners. The way the flow column enters the port is also a consideration.

I find the SCJ runner intakes down on torque vs. the smaller runner rpm and T2 by some 30+ pound feet at peak on a 466" deal.





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BBFTorino wrote:If you want the higher RPM power, then I would think that the Weiand Stealth would be better, no??

I am sure the best direction for you, and anybody else can go, is whatever avenue you THINK ...whatever will make YOU most happy with your decision

"When testing, if the results differ from your theory ... believe the results and invent a new theory", Mike Urich

I don't know when people will finally realize that a BIGGER runner will usually flow more air but, won't necessarily make more horsepower and torque. And, definitely not more torque below the RPM of peak torque.

It is all about port velocity below peak torque.

SandHillsHillbilly wrote:It is all about port velocity below peak torque.

Everywhere else too...




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Thanks to all for the input. Scott's explanation makes sense. My only question now is between the RPM vs T2 with power cone, is there a significant advantage at the top end with a T2 and if so, at what cost to the bottom end.

Thanks again to all.

Staci

69BOSS wrote:Thanks to all for the input. Scott's explanation makes sense. My only question now is between the RPM vs T2 with power cone, is there a significant advantage at the top end with a T2 and if so, at what cost to the bottom end.

Thanks again to all.

Staci

Ultimately which intake you pick would depend on the type of vehicle and intended use.

In a best case scenario your engine is going to make about 520 Hp (IF THE HEADS ARE PROPERLY PORTED)

Build for as much torque as you can in the RPM window the combination will be most used. The HP and seat of the pants dyno happiness will follow. Good average numbers get the car down the track faster.

If your heads are not ported leave the intake as delivered.



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I chose the stock cast iron SCJ for the MOST low end torque.

gt350hr wrote:    I chose the stock cast iron SCJ for the MOST low end torque.

In multiple dyno tests I have found the CJ port intakes including the stealth, blue thunder CJ and the D0OE-R SCJ to ALL be down 20 to 30 pound feet at peak vs the RPM with port matching at the roof.





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gt350hr wrote:    I chose the stock cast iron SCJ for the MOST low end torque.

The stocker works better that most think. I like the Blue Thunder DP.