Upgrades?

apats77 said:

Ok here it goes: 1998 Mustang GT (5 spd)
Port and polishing a NonPI 4.6L.
What are somethings that get P&P that I can do myself?

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Polishing is an old school term that doesn't add much for performance. Having a slightly rough surface creates a boundary layer and actually can increase flow (think golf ball). As far as porting, there are a few members on here that can do porting of their heads themselves but if you have never done porting of a set of heads before I would probably have someone else do them or someone with experience to show you how. Most people on here buy the PI heads, they are a direct bolt on to your NPI shortblock and flow better in stock form.

apats77 said:

How big a difference will that make?

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Porting can add decent hp but it will do better with supporting mods like a cam that can use the porting.

apats77 said:

Cold air intake vs just a K&N replacement fiter? (money tight)

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If money is tight you could: 1)Replace the filter in your air box w/ a k&n. 2)Replace the airbox w/ a k&n cone filter and keep the stock intake tubing

apats77 said:

Best bang for your buck Clutch.
(This is my first manual)

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If your clutch is working fine now then there is no need to replace it. If it is slipping / making excessive noise, etc. Then.... assuming your car is mostly stock.... the best clutch would probably be an OEM stock replacement clutch.

apats77 said:

180* Thermostat? Pros and cons?

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Not needed a stock car with a properly running cooling system. 180* thermostat is for forced induction cars / engines that are under lots of stress and produce lots of thermal energy.

apats77 said:

Where can I find a replacement cone filter that eliminates needing the airbox?





Since money is tight would I benifit from porting the Intake manifold/Plenum/ Polishing the TB?

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K&N Mustang Drop-In Replacement Air Filter (96-04 GT) at AmericanMuscle.com - Free Shipping!

You will not be able to port the stock intake manifold, it is made with composite plastic. I would read up on the PI intake swap. Here is a new PI intake (install instructions are also on that site):
Ford Racing 4.6L Performance Improvement (PI) Mustang Intake Manifold at AmericanMuscle.com - Free Shipping!

I would take polishing completely out of your vocabulary. Polishing offers absolutely no performance gain.

As far as porting goes- you will not be able to port the TB a significant amount. You can port the plenum but with a stock engine you are looking at very minimal gains (1-2 hp?).

What you should do if you are looking for the best bang for buck with your 98' stang you should do a "PI swap". The easiest version is to swap out the NPI cams and NPI intake manifold for PI cams and a PI intake manifold. There are a million threads describing this install and a quick search will yield lots of info. PI cams can be bought used for pretty cheap. If you do the labor yourself you are looking at <$300 in parts and a good 20+rwhp gain.

This is a pic of a Terminator airbox but yours will be similar. The silencer is the flexible rubber bit on the plastic airbox and it extends into the fenderwell. It can be prised out easily from the airbox housing.

apats77 said:

So am I holding the silencer in the picture?

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Yes.