96 Ford Cobra HELP?????

[Freddie]

I am working on a 4.6 4v Cobra motor for my 90 Mustang that I am looking to race NMRA Factory stock with for now ( Hopes to convert to NHRA GT car later). I know there are a few tricks to make these motors work, and even in true factory trim they make decent power, but has anyone run one? What are they capable of? NMRA Factory stock would be about the equivalent of a NHRA Stocker as there is no porting OEM spec cams, and factory intake and throttle body.

ANY help is greatly appreciated....

[Tony Corley]

To even think about building a competitive 4v for Factory Stock, the only parts you have that would be worth using is the block, and possibly crankshaft. The desired parts are 03-04 heads, aftermarket cams, 03-04 mach 1 intake, etc.
Jesel cam followers (32 at $100 each). Billet rods, lightweight pistons, lightweight valves. You are picking the most expensive to build, least competitive engine combo for the class. Jay Dold has been the only one in a long time to even try to field a competitive 4v in the class, it is state of the art with the best parts, and it still is barely competitive. Jay is a friend of mine, as is John Leslie Jr.
The heads you have (96-98) and intake do not run good n/a.
You would be better off to keep your block and crank, and run a set of PI 2v heads and factory plastic intake off of a 99-04 Mustang. That's the combo Matt Amrine, John Leslie Jr,, and I think Louie Sylvester Jr. are running. I even have specs for a set of cams that will get that combo in the ballpark, if you go that way.


I actually once owned the car that John Leslie Jr runs, and bought what was at the time the quickest F/S 2v engine/trans combo in the country from Jim St. Charles.


They do not use oem cams in any engine but the Coyote. Everything else is allowed to move duration and lobe centers, only lift is specified.


If I was going to build a F/S car right now, I would start with a Coyote engine in a Fox. It is still required to use factory oem pistons, heads, cams, etc. You could buy one form a late model Ford truck for around $2000, and swap cams and intake. Or you can build your 4v and spend $5000-$7000 on a competitive 4v shortblock, and another $8000 or so on 4v heads.
32 lightweight valves $900
springs $500
Followers $3000
Cams $1200-1500
castings $600
retainers and locks $ 500
valve job $1500


And after all of that, the 4v has not had a favorable weight break in years. Jay's stuff is built, tuned by Tony Bischoff and Tim Matherly, and he can barely run the numbers in a car that has been science out from one end to the other.


Not trying to put a dampner on your parade, you asked for opinions, and mine are based off of being around and knowing a lot of people in the class, and buying a lot of combos over the years.

[Freddie]

Tony, thank you, for the info. I am reaching out to Jay as well for some info. I have also been in contact and working close with NMRA Tech for the needed weight breaks to make not only the 4V competitive but the "B" head as well. We hit the dyno with our first motor and was pleased with where we are for a starting point.

So has NO ONE ELSE EVER run a 4.6 DOHC setup in NHRA Stock trim?

[Tony Corley]

I have no idea on NHRA. Jay is a good guy. Tell him I said hello. If you can get a B head weight break, that may help. They finally gave the 4v's cams a year or so ago, but it may have been too little too late.