Hope this doesn't sound like a dumb question, but could our 3v heads be swapped for 4v heads from the 03/04 Mach 1.

That is.. providing their compatible, and are of similar design.

 

interesting idea. what kind of gains would that kind of swap make?

 

I can't answer your question really. But I will ask why you would want to switch?

In stock form the 4V heads do allow a slightly higher redline and might breath a tiny bit better up top. But from what I have heard and seen. The performance differences are very small and the weight difference between them is very large.

 

No they don't fit unless you make some sort of frankenstein intake. Might be some other problems too.

 

would be better off doing a complete engine swap

 

I know there isn't anything to be gained powerwise. I was just thinking that if the swap could've be done fairly easy. It may have also been a possible alternative/fix concerning the 2 piece spark plug issues.


However being that such a swap would also require changing the timing cover, timing chains & gears, water pump, intake manifold and TB. Not to mention having to re-tune your PCM, because you'll no longer have variable valve timing, but instead would now be running a four cam setup.

Therefore It's obviously way too expensive, and just isn't worth all the hassle.

In the meantime, I'll just wait until Ford comes out with a new one piece plug design.

 

If you want to make big power naturally aspirated the 4v heads would be a worthwhile idea since the 3v heads are only good to about 400hp or so without some kind of help from a power adder on a 4.6L engine. If your plans keep you beneath that number then, IMO, the 3-valve heads probably make more sense from a drive-ability and value stance. That said, if the future potentially holds really big numbers any of the DOHC heads have far more potential than do the 3-valve units, and the newest pieces used on the GT and GT500 are in another class altogether.

Still, a simple head swap isn't really plausible. I'm sure you could retain your short block if you wanted to but the changes needed elsewhere would be significant enough that it would be like performing an engine swap if I had to venture a guess.

 

My purpose for suggesting the swap, had nothing to do with a power advantage over the current 3v head design.


It was just an idea that I had, as a possible fix/alternative for the 2 piece spark plugs breaking inside the 3v heads.