classix_stang289

Im looking for some reading material. Does anybody have any websites describing how the new 3valve motor compare to both the 2 valve and the 4valve. any help would be appreciated , thank you

281GT

There's lots of info out there but basic physics tells us that with increased breathing abilty comes increase performance therefore, all other things being equal a three valve has greater potential than a two, a four valve engine better than a three. Looking at typical hp and torque data from the different types you will see this reflected.

DynamicmustangGT

Is there anyway to put 4v heads on our 3v's to add performance? Or would the pistons not like this idea? and does anyone make a swap kit like this?

Speeddmn

it can be done, the heads will bolt up but you then ave to get the nessary hardware, front cover, lower intake, upper intake, hoses, and so forth. Basically the same as doing a 2v to 4v swap. Can it be done, yes, easy, depends on your ability to look and solve a problem, and or pocket depth. I'd love to do a 4v swap, but a good port/clean up on 3v heads and they flow pretty dang good for anything I want.

Stock to stock 3v to 4v staying n/a yo umight see 40 ish rwhp, maybe. That just a ball park guess. But would cost 2k or so if you dont have anythig on hand already. NOt to mention new headers, tune, etc etc.

mrkabc

In other words: NOT WORTH THE EXPENSE...

wsmatau

Definitely not worth the expense, IMO. Our 3V heads flow VERY well. Although the 4Vs can flow more, you'd really have to be pushing the limits (over 500 HP) to see any benefit. For the little additional flow the 4Vs have, it comes at the expense of additional weight. For a street car you're not going to see a return on your investment.

Rebel73

I read in one of the mags that the 3V heads flow just about as well as the 4V, if not better. It has something to do with the angle as well. Wish I could dig up that article...

in any case, I agree, it's NOT worth the exepnse. Put that dough towards a blower!

tom281

Remember, just because a head can flow more doesn't mean that it necessarily will.....

70MACH1OWNER

Very good point. And to add facts to this statement. I owned a 1996 4V Cobra that came from the factory with 305 hp. Trust me these new Stangs with the 3V heads and 300 HP would out run that car hands down.
Scott

RobK

+1 My '97 4V Cobra had 305 HP vs. the S197 with 300 HP. I'm sure the 4V had more potential, but I don't think the gains you would see would be anywhere near worth it.

97svtgoin05gt

Just curious, my last ride was a '97 Cobra vert and I honestly felt the two cars are about the same. I did put 3.73 gears in that car and let me tell you, it's exactly what the car wanted. Once they were in there, it was like a totally different car.