I think the 4v head on the L would be an excellent way to increase horsepower and torque. Many on this board have added pulleys and increased low end torque the point that they can spin the wheels all day long. Unless running slicks it hard to apply all that low end power to the ground. Now if you have a 4v head and pulleys, I would think you would still have plenty of low end grunt and gobs of power up to the 5250 shift point. I would not rev the motor any higher. I think the recent discusions regarding long tube headers point out that with additional boost pressure from 3,4,5 pound pulleys getting rid of the exhaust has become an issue. That tiny exhaust valve just does not get it.

This would be an excellent mod for Ford to install as a counter to the as yet unseen Dodge truck. To do this as a owner mod seems like a real project; but as BA said if you are into it its just fun. My nickles worth.

 

I had thought about going with a set of 4V heads, but I decided against it. For one it would have been to expensive, and I didn't want to loose any low end power.

I am putting larger valves both intake and exhaust in my stock heads, and am not touching the cams.

I hope this will maximize power throughout the entire rpm range of the motor.

 

Here are the photos of 2V vs 4V intake and exhaust ports...first pic is the 2V intake port:

 

4V intake port...

 

2V exhaust port...

 

4V exhaust port...

 

Perhaps something has changed, I looked into this awhile back and as I remember you can't increase the valve size enough to help...

If you go ahead with it, keep us posted..