Home porting question

[Agent_4573]

Hey, I just got an explorer upper/lower intake and was thinking about porting/polishing it a little at home before i put it on. I've heard people talk about gasket matching on here too. What all is involved in gasket matching? is it basically just taking away the intake until the opening is the same size as the gasket? How hard is it to screw up? My dad has been a mechanic for most of his life, but he has to work over thanksgiving break so I'm probably gonna be doing this mostly on my own. I was thinking about just opening up the upper a little and doing a full polish job on the lower intake. I hope you guys can help me out cuz i wanna try to sqeeze every hp from this thing...


P.S. Should i polish the egr spacer and throttle body while I have em off the car?

[Stang39r]

i too would like to know how to polish...sorta in the same boat as you but ill be doin it over winter break so i have a long time to do it

[84LX89GT]

I've heard that when you port match things, basically what you do is scribe a mark around the hole where the gasket is (depending on what type of gasket). If it's the new style with rubber sealing o-rings, i'd scribe pretty much at the port hole, if it's an old style gasket (plain looking, silver), then i would probably leave 1mm or so until the gasket all the way around. The key is just matching the sides together and blending the match about 1" or so into the cylinder head and intake manifold. If i were you i wouldn't polish the lower intake manifold because since it's right before the fuel injectors you want a little bit of turbulance to pick up and swirl around the fuel so it doesn't get stuck to the port walls or pool anywhere. Using a fine grit sandpaper cartridge for the lower intake is what i'd recommend as an end finish. If you wanted to and had the time, polishing the egr spacer wouldn't hurt (although i'm not sure if it's rough at all to begin with, and the throttle body you probably should just clean out with a throttle body cleaner (although ford doesn't recommend this because of the Teflon coating, all the throttle bodies ford makes gunks up anyway so Ford is smoking something funny).
While you're in there, you may want to gasket match the exhaust side of the heads and grind down that enormous thermactor bump flush with the port. Polishing the exhaust would possible help as well.
I'd say if you're putting an intake manifold on stock heads like i did, gasket matching/very light porting should be worth at the very minimum 10-15 horsepower because of the differance in port sizing especially on the intake.
Good luck,

[2FastLX]

84LX89GT is right. You don't want to polish the lower intake, or the intake ports in the heads. You don't want to go any further than 120 grit cartridge rolls with it.

With stock untouched heads I really don't think there is a lot to be gained by porting the intake, but I'm sure it wouldn't hurt. You'd gain the most horsepower if you pulled the heads and did some work on the exhaust side and in the bowls. Then a gasket match on the intake side would be more beneficial. I saw an article where they picked up 30hp just by smoothing the short-turn radius, which is the area under the valve head that makes an abrupt turn into the port.

If it were me and I was going to go to all the trouble to pull the lower intake I think I would go ahead and pull the heads and rip some metal out. There's a lot to be gained on a set of stock heads

[Agent_4573]

I'm not to worried about the heads right now cuz there gonna be replaced by gt40p's within the next year. When i get them im gonna do a port/polish job on them before i put them on. I just want to get the intake all prepped so when i get the heads later i don't have to worry about the intake at all.