Creetan

Ok Guys here is the deal. I am new to the 4.6L mustangs. I always herd the 5.0 was a better motor and had better potential. However after having a 88 Fox body with a built 302 and then a Procharged 94 I feel its time to move on to the 4.6. Here are my plans I want to buy a 1999-2004 GT and put a KB on it running 9psi of boost. What I want to know is what are the key things to look for in a 4.6. I have been looking around and see alot of people selling cars with rebuilt engines cause of some failure and it was covered by warranty. Does the 4.6 have any major issues that I should know about? Also whats the pros and cons on the 2v and 4v. I herd the 4v didn't flow that much better. Not sure if thats true or not. Also out of the 1999-2004 was there a better year to get? I am looking for any info about these cars at all. Thanks alot for your input and sorry for the long post.

Aereon

styling wise, 01-04 gt's look better imho.. 4v's flow way better than 2v's, 2v heads suck, 03/04 cobra with a kb at 9 psi will see about if not more than 500 hp/tq. 99 cobra's have very bad irs's that will need a little work to make as effective as 03/04's. 96 cobra's have one of the toughest blocks.

Thats pretty much all i can think of atm

Creetan

Also what year/models came with 2v heads and what came with 4v heads? From what I seen cobras and Mach 1s came with the 4v. Thanks again.

cahtr6

Anyone that says 2Vs dont flow better go check out the MPH forum. A GT with 2.8 K/B made 832HP and 827TQ thats with ported PI heads Go Kenne Bell!

72MachOne99GT

Don't know if this guy is still looking around, but if you're planning on FI... depending on what kind of numbers you want to see, the 2V isn't THAT horrible of a choice.

A good set up, with full exhaust and some gears and DR's should net you well ito the 12's in the quarter mile wouldn't everyone agree? Sure, thats not super fast, but it's not slow by any means either.

96-04GT = Anemic 2V (96-98 worse so than 99-04)
96-99,01 Cobra =4V (99,01 have IRS, 305hp for 96-98 - 320 for 99,01)
03-04 Mach - 4V (solid IRS but has same block limitations as the previous 99,01 Cobras) correct?
03-04 Cobra -( if you still have to ask, there is no way you're interested)

ShadowDrake

The 2v isn't THAT horrible, if you don't mind having the CFM of a coffee straw.

The best P&P 2v head only outflows a STOCK 4v head by about 5%... P&P the 4v and you outflow the best P&P 2v by 80%+

Edit: Cobras and Mach1's have the 4v. GT's CAN be swapped to 4v heads, but a pair of bare 4v heads is $900, add 4 cams, 32 valves, springs, and all the other necessary hardware to them and they're pretty expensive. The GT block will have to be modified to fit the 4v timing equipment, it's not a major modification though, still, one that you can probably not do with the tools in the average garage.

The 2v motors have no major problems, mechanically speaking, the 2v head is pretty good, doesn't overheat, has no major issues other than LACK OF AIRFLOW! The 4v heads have a cooling issue on the number 7 & 8 cylinders (farthest back two on the passenger side). In N/A form, this is not an issue, but if boostedthe best mod to be done is to drill out the freezeout plugs on the back of each head and run a coolant hose connecting them, so the coolant doesn't sit in the back of the passenger side head and cause heat to build up,leading detonation and an early end to the motor.

Other than that, any 4.6 motor except that in the 2003/2004 Cobras will lose its bottom end at about 450-500 RWHP (sometimes lower)... The connecting rods are weak powdered metal, and they break, the next thing to break are the hypereutectic pistons... The cast crank is not bad, but if you're upgrading the rods, replace the crank with a forged piece. The 2003/2004 cobra motor already has forged pistons, rods, and crank, and is good for much more power (800 rwhp is about the limit). 4.6 blocks are never a problem, the cast iron block in the 96-04 GT's is VERY strong, Cobras and 05+ GT's have an aluminum block which is still strong, but not as strong as theiron block. Early cobras have an aluminum block made in Teskid which is VERY VERY strong.

That's about all the random info I can spout