Missmy5.0

I have a FRPP Cobra/GT40 cast (non-tubular) intake on the way, and a 65mm FRPP Throttle body on the way.

From what I gather, I don't NEED the 65/67mm EGR spacer Ford used to sell. I assume that was only to use with a stock intake, since the stock upper does not have a provision for EGR, and Cobra upper does. (Do most aftermarket upper intakes not- they all seem to sell spacers as a separate item). As I understand it, the coolant lines that went to the stock spacer should be joined to bypass the spacer.

1) Is there a benefit to using a spacer even with the Ford TB and Ford Cobra upper? Is there a drivability/emissions issue ? (I am assuming there was a real reason for the original coolant flow through the spacer).

2) Since I am using the stock air tube (with KN filter in original box) would TB/spacer/intake combo be too long, making fitting the snorkel over the new TB difficult (I'm assuming the upper intake is longer already to make up space)

3) If there are reasons to use the spacer, are most all compatible? It seems like a pretty basic piece, and most of the aftermarket look the same except for finish.

As far as the MAF, it sounds like a 70-75 mm unit is the way to go, but anyone's experiences are welcome. I like keeping it "mostly Ford" but I am certainly open to ideas.

I should add that this convertible is a fair-weather only cruiser, and though I'd ove to swap in a 5speed, I'll be a great grandfather before that happens (my kids are in grade school). I do plan on replacing the heads and cam when I replace the intake, right now I'm gathering parts. I've been persuaded to go aftermarket by my fellow members unless I can find GT40X heads at a low price.

Thanks for any and all help!

mjr46

no spacer needed for cobra intake, save your money for gears since it's an auto car

Missmy5.0

That's all the encouragement I need! Now the decision...3.08, 3.27, 3.55 ....

dawson1112

autos benefit greatly with 4.10 gearing , I would not even bother with the 3.08 or 3.27. but 3.55 3.73 or 4.10 will give you a really different driving experience in that car. It will feel like you just gained a ton of torque.

Missmy5.0

Interesting- I would have never considered anything over 3.55, just based on experience of friends when I was a teenager. They all rushed to put 4.11s in their Camaros and Chevelles; they'd shred tires, but the TH350 or worse Powerglides, shrieked at anything over 55mph.

The overdrive would make a big difference I suppose, and this is a cruiser, not a real highway car. God knows it needs something to wake it up. My 87 5speed LX was much quicker- it always felt ready to jump-and this convertible feels like such a dog in comparison. truth be told, our 4.0 Chrysler T&C feels smoother and faster. I have always been afraid to really push it because I don't know the real condition of the transmission and I have heard they can be like grenades, It definitely has a VERY lazy shift between 3rd and OD. I don't have the dough for a rebuild or a 5 speed swap right now so I'm pretty conservative.

The 3.55 or 3.73 sound like my best bet (factory was 2.73, correct?) especially i am a couple years away from my oldest daughter driving....

dawson1112

I am not to sure what your stock gears are with out knowing the year . You could have 2.73 3.08 or even 3.27s My stock 94 5 speed came with 3.08 and I upgraded to 3.73 traveling at 65 on the freeway in 5th gear I am at about 2300 rpm.

Duncan_GT

4.10's or 3.73's are the most popular gears. Your overdrive will help on the highway if that is a concern

Missmy5.0

The axle code in door is M, or 2.73, and I would doubt that was ever changed- the car still has the intake silencer, factory exhaust etc.

2300 rpm at highway speed with 3.73 gears is impressive! The popularity of those ratios- 3.73 and 4.10- tells me they must be the sweet spot for the Mustang. Fuel economy is not a concern, since this is a fun car, and not a daily driver (my commute is 5 miles anyway).

My only concern would be exhaust noise- the factory mufflers are getting a little raspy, and will need replacement in the near future. The one thing I dread is the "5.0L drone" I had when I got new (Walker?) mufflers back in 91 on my 87. My drive then was 150 miles round trip, and the noise was horrible at 55 mph. If I am using a lower axle ratio, I am afraid of a drone at a lower speed if I get the "wrong" exhaust. I recall that Ford used slightly different muffler sizes to beat the drone. I am not sure that when I upgrade heads/intake/shorty headers that the exhaust will be a choke point. In the dustbin of my brain I remember reading that the crimped factory headers were the real problem, and that with larger exhaust valves and shorty headers the factory cats on back were fine, that the performance mufflers were more about sound. I'd like a bit more growl (my kids vote yes, wife votes no) but not the drone.