I've read in a few places that the 4.6 which was in the SN95 body styles is sluggish compared to other Mustang motors, even though it has the same HP/TQ ratings as the older 5.0L's had - what validates the idea that they're slow?
I'm also interested in the differences between the 215HP 97/98 4.6 SOHC, and the advertised 260HP 4.6L SOHC in 1999 and newer GT's. I thought my 97 GT had basically the same motor as the 99+ GT's, but obviously that's not the case. I'd just like to know what the differences are between the 2.

 

The diff in the 99-04 Gt is the PI heads (performance improvement) PI intake and Cams. On our 96-98 engines the experts say our heads are the weak part in this engine. The 96-98's just lose all go once they get to 400 rpms. Ford fixed that problem with the 99-04 revised PI Heads, intake and cams. If you install the PI kit you gain at the least 55 rwhp. The PI kit is a must have for the 96-98 engine.

 

The PI swap will also raise the compression. When you do the swap you will have basically have the same motor as the 99-04.I dont no why Ford rated the 96-98 motor the same as the 94-95

 

The main difference between 2v and 3v Mustangs.....

Ahh, well the 3v actually responds well to modifications. It takes a sickening amount of work to get near 300rwhp with a 2v. Whereas with a tune and 1,000 bucks worth of mods or less a 3v will surpass 300rwhp.

 

What's a PI swap worth? (parts and shop labour)

Are the 99+ 4.6's a 3v? Dan's post confused me ... I thought all the 4.6 GT's were 2v, and the Cobras were 4v's ... ? As you can see, I'm a newbie to 'Stangs ... learning a lot though!

 

Yeah Dan ment to say 4valve heads are offered on the 99-04 GT STOCK. You should read the FAQ section and it explains the differences in
there quite well.

 

2v heads are the only heads available stock for a 99-04GT.

4v heads come on 2003-2004 Mach 1.

4v Heads come on 96/97/98/99/01/03-04 Cobra's.

3v Heads are on 2005+ Mustang GT's.

 

Back to your original question, the 4.6 in the SN95 has the same power ratings as the older 5.0, however the car with the 4.6 is slower because it's heavier than the Fox body 5.0 Mustang that it replaced. In addition, the 5.0 has a world of aftermarket parts available to it, where the 4.6 doesn't have that inventory yet.

In addition, from this forum I was led to believe that ALL 2V heads suck, despite the increased flow of the PI setup...

 

the newer pi's dont suck, they alowed the mustang to make 1.07 ft-lbs of torqe per cubic inch, not bad back in 1999

260hp/302ft-lbs makes for a fun street motor, enough to hang with lt1 gm f-bodys. but yes i think that ford should have designed things faster and put the PI stuff on th 96-98 gt's and the three valves on the newer 99-04 and then go to big bore 5.0 for 05+
that may have changes history for the mustang in the mid and late 90s when the f-bodys were handing us our ***'s

 

slap a blower onto a 2v and you'll have all the power you'll need.