I got a 94 4.0 with custom exhaust, and intake. Now i was looking into polishing my intake manifold and head. has anyone tried this and what gain of power did u get.

 

I have not tried this on the 4.0, but in most cases the intake passages are best left as cast to retain some turbulence to keep the air-fuel mixed well. The point where performance can be gained is in matching the size and shape of the manifold-head juncture. Go ahead and polish the exhaust ports, but don't make the port too big or you will lose velocity.

 

Yeah thats one point that got brought up on Ford Enthusiasts, but one guy said u only had to worry about that on carbs were EFI dosnt mix in the intake manifold were carbs do.

 

Good point there, if you decide to go for it let us know the results.

 

I know 422 cam, p&p heads, and tune will get about 40rwhp.

Assuming you have flow to support it.

 

Yeah, but as i read on they say that porting with a ruffer grit it better, Like its better to port with a ruffer cut then a polish,, Theres so many opinions out there lol ill just have to keep reading and get more opinions

 

You polish the combustion chamber and the exhuast port, just open everything else up.


To get to the 40hp mark you need to do more than a gasket match. Porting is a skill at least if you plan to make horsepower it is. There is a reason places charge 1600 for a set or ported and polished heads.

 

Oh yeah thats another thing what about new gaskets. And yeah i can do, iv worked with metal for 10 years and got steady hands with a grinder. And im not goin to do a real big port

 

You better off swapping a 5.0 and P&P those heads you'll gain more than a 4L you also can run a carb instead of EFI

 

Well hell yeah id love to do that, do i dont have the money for another motor.