Contour Enthusiasts Group Archives Forums Modifications Duratec Performance ported and polished heads

Good point Trevor.As to the valves I'm still a little lost! The 2.5s are 32mm intake & 26mm exhaust,the 3.0 is 35mm intake & 30mm exhaust, so I dont see how the 2.5 heads on a 3.0 will breathe? If its only for the waterpump, the latest 3.0's have gone back to the waterpump in the same position as the 2.5 so the 'swap' should be easier!

I'm a little late...but I am PGTATX on the cougar board. I am having a full port and polish w/3 angle valve job done for a helluva lot less than $600 per head. I can't tell you how much i paid, for obvious reasons, but I can tell you, for appx $750-$1000 total, the person doing my heads will do a set for you with everything.

I am also adding SVT cams, SVT injectors, a P&P lower intake manifold, new plugs and wires, Quaife LSD, Fidanza flywheel, and a PAC chip (maybe). Along with my other bolt ons. I already dynoed 172.9whp with no headers, and just the common bolt ons. So, i am hoping to see nice gains. From what I've been told, these heads have an excellent race setup, and have obviously been detuned for economy. The heads are very restrictive.

I was asking about using larger valves, and he told me he could do it, but it'll be really tough since there is very little room around the valve seats to begin with, but he could do it. I opted to stay with the stock valve sizes, and just get the 3 angle job.

He is currently on a trip to florida to build up someones engine, so My heads are awaiting delivery. Once I get them installed, i will post Dyno numbers, and then you can all decide what it's worth to you.

I am hoping ti get enough power to pull a 13.99 or better from all of my current mods, and the ones I am adding. On street tires, with the exhaust, without too much weight reduction, and on the stock 2.5L block. So I'll see.

About SVT heads being Extrude hones already...Many peolle think extrude honed and porting are the same...the polishing part and the extrude honing are equivalent. Extrude honing smooths out the metal, as does polishing...porting actually opens up the openings to allow more flow. If you ported out an extrude honed thing, you;d remove the extrude honed part. So Porting and polishing will yield more power or atleast air flow, rather than just extrude honing.

I should have pics to post of my heads, so you can all see...

If you know anything about multi valve race motors you should know 1)Gas velocity is more important than flow 2)Polish or 'extrude hone' is NOT the only way to get better flow/less 'boundry' friction 3)The 2.5 gas velocity will 'die' if you go too oversize with intake valve. Just my 2 cents from many years on the Cosworth F1 motors of the 70's-80's !

Terry,

I think that the main reason for the 2.5 heads where three-fold:

1) the 3.0's wouldn't clear the hood.
2) the 2.5's allowed higher compression, thus more power.
3) the water pump placement ... no longer an issue with 2001 3.0's

Someone correct me if I am wrong.

11:1 is pushing your luck with a 'stoc' bottom end,still think it was for the water pump!

So,

since we're able to use the 3.0 heads b/c of the new water pump placement, what will yield more power in a 3.0 swap?

1. 2.5L SVT heads?

or

2. 3.0 heads with a port and polish job

I know it's not that simple, but what would *you* recommend? Obviously using the 3.0 heads will yield lower CR, making the motor possibly more reliable, correct? What's the stock CR on the 3.0 Duratec? Is the stock 3.0 strong enough to handle some boost? (Be it a supercharger or Turbo)

Very interested in this... Very interested in your stuff as well Terry, rods, crank, etc.... Figure if you're gonna do it, do it right so it'll last.

John

Stoc 3.0 is 10:1

I thought our crank was stong enough to begin with? 4 Bolt Main? Forged? hmmm.... Oh well, If i am gonna upgrade the pistons and rods anyways (JE and Crower should be good enough for me) then I my as well do the Crank if the cost is reasonable ....this whole engine/drivetrain build up is already gonna cost about $10,000.00 for all the parts and labor..my as well just add on some more money to the total.....heheheh...


Nik

"About SVT heads being Extrude hones already...Many peolle think extrude honed and porting are the same...the polishing part and the extrude honing are equivalent."

Depends on how much "Honing" you do
Mild Extrude Honing only removes surface "flaws" and givers a rough polish. This is what the "single Honed" 98 SVT upper intakes have.

Moderate Honing gives a more mirror like finish and does mild porting (increasing port diameter) say 1-2mm. This is what the "double Honed" 99-00 SVT uppers recieved, as well as the cylinder head intake ports.

Extensive Honing can be done to really open ports up. An example here is the SHO-Shop 37mm upper intake (sent to Extrude Hone). The nice thing about Extrude Hone porting is that because the silica-putty material flows through passages like air, metal is preferentially removed in areas of the most restriction to flow. Hand porting doesnt do this (not to say it is bad).

The 3.0 heads that have been ported and polished will certainally be better for a 3.0. They might be better with the 2.5 as well, but there is a chance that they might be a bit too big. I'm guessing that they would be great on the 2.5, but someone needs to try them and do some dyno runs.