MrSandman

Neither.. since both were made to optimize different engines. The boss motor is not just a different intake.. and the CJ.. is.. well.. different. They were engineered with a package in mind. The stock 5.0 was not that package. You will need supporting mods just to get a real difference.

Remford

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Holy Cow. 4.10s with a 6AT? I've just taken delivery of my '14 GT to round-out my garage - which I intend to use as a high-performance daily-driver alongside my track-dedicated cars. I chose an AT for the sake of having one that I could hop in and drive just as easily in traffic as on the road course.

I've not yet done a manifold swap since I already have a 302. But with the Ford Racing Power Upgrade intake in tune, I've been thinking about shortening up my gearing for a little extra low-end torque. 4.10s must have hellacious pull. I was thinking 3.55s from the OE 3.15s. Which would you recommend?

Thanks in advance.

scottmach

Stick with the 3.15's. There's a reason Ford used them in the autos. The gearing in the transmissions are aggressive to begin with. A converter makes a significant difference.

Shane780

To be perfectly honest your not going to see much of a performance gain with just bolt ons and gears. Decide on how fast you want your car to go and go from there.

The easiest way to go faster but also an expensive way is a supercharger kit.

By the time your done getting the cobrajet intake matching throttlebody, 4.10 gears (cause you have no low end torque) the high rpm ring installed, and a tune with some data logging and a retune for 20 hp(you lose horsepower by going to a steeper gear set). It may be close in cost to a supercharger. I don't know how much the bottom end on the Coyote will like spinning at 8000rpm or for how long, cause thats where yout shift point will be at.

Supercharged automatics run 10s on slicks.

learning

I am currently running 3.55 gears, with boss intake,,bbk 85 throttle, Airaid cold air and bamma tune. Eibach Pro Suspension and BMR panhard and I have problems getting tires to lock. Last year ran with just gears and Cold Air with tune and car was fast. With new intake and throttle bottle it is differant car. Great low end and can break tires lose at over 40.

Mishri

It depends on your goals with the car and what you are willing to accept. I lost about 3 or 4mpg with the 4.10s on the highway, picked a couple up in town, it amounted to about 21mpg average for me. I don't drive the car that much (only 11,000 miles, mostly long trips on the highway).

For optimal 1/4 mile times I believe 3.55s are ideal. (so you don't shift into 5th I believe) I think the next step from there is 4.56s. (been awhile since I looked into it) The nice thing about having the automatic is I don't have to worry about how short 1st and 2nd gear is..

I enjoy the 4.10s.. I don't expect everyone to.

As far as the boss being a different engine... just barely. only things different that might apply is this:

Hi-Lift Exhaust Cams
7500 RPM Limit
CNC’d Heads

(assuming the list I just looked at for differences is accurate)

and you can bump the RPM limit up.. Plenty of people have seen gains with it, but yeah, CAI+exhaust helps a lot with the boss intake manifold. (some people got lower 1/4 mile times with it, my guess is they couldn't drive it properly, as the fastest 5.0 bolt-on only times I've seen are all in Automatics with the boss intake manifold)

LaMotta

we are going to try the cobra jet intake with boost on our i-1 procharged 5.0! going to fab a silicone fitting for duct work on our procharger to mate to the CFM gt500 67mm twin throttlebody into the manifold. should be beastly!

JIM5.0

I just found out something very intersting in an issue of 5.0 mag a couple of months back: The CJ intake has the exact same intake runner length as the Boss manifold.
The runner lengths indicate to me that the output curves (HP & torque) of both a CJ engine and a Roadrunner engine will occur at the same RPM bandwidths. The only caveat being the CJ engine will have a massive amount more HP.
The shape of the HP and torque curves will have the same shape for both engines; the CJ engine will just have its curves shifted up in their axes (no, not what you chop trees down with).
Additionally, the CJ intake has a larger plenum, larger intake throttle body mount, larger diameters for the runners, so it is capable of holding much more air to be fed into whatever hungry engine it is bolted onto.

The difference in cost between the two intake units are:
Boss 302 manifold: from $475 - $520
CJ manifold: $750 - $850

The Boss 302 manifold can accept the stock throttle body (I think, someone please correct me if I'm wrong).

The CJ does not come with an intake throttle body, so you must buy one because the stock one will not fit.
Some aftermarket ones will cost as little as ~$350.
A GT500 throttle body will cost ~$650
Ford Racing sells the single oval throttle blade throttle body for $680.

I, being the naive one, thought the CJ manifold came with the throttle body for that $850 price. I did not know that I would have to spend another $350-700 just to buy the throttle body to go with it.

VistaBlueFrank68

Won a Drag Race because of the top end performance boost with the Boss intake.
Quote "I kept up with you till the very end then you just took-off".
A happy customer I are.