deesgt

So I'm in the process of choosing a Mustang to purchase and honestly I'm leaning towards a 98GT Vert. I know the horsepower is alot less than 99+ but I can sacrifice that. I plan to make a few mods to it anyhow. Thing is...I'm not real concerned about 1/4 mile times or anything. I just wanna have a nice lookin car with some power underneth my foot if I choose to unleash it. I work for Ford and I would like to keep this car for maybe 2 years and then go to the new body style. I'm sure by then all the hype will have died down. As for this car if I could get it up to 300 rwhp N/A...I would be a happy man. I have been reading alot and educating myself on Mustangs and just cars in general but there are still some things I'm not too clear about. On to the questions (no laughing)

What is a plenum exactly? and do you have to get both it and a throttle body?
When I see the term PI head swap...is that the same as "headers"
When you change a stock exhaust...what parts or necessary? I'm confused on cats, catback, x/h pipes, etc.
My car will be an auto. I've heard you should go with 4:10 gears on an auto tranny. I visit my mom in Georgia (900 miles one way from St. Louis) will this be too high of a rev for that long of a drive?
Is it possible for me to get 300 rwhp N/A out of this car and if so what will it take?

Thanks for reading. Hope those were'nt too dumb for yall!!

Razor19

The plenum is the thing with the mustang on it underneath your hood. No you dont have to get a throttle body with the plenum but upgrading your throttle body will help your perfomance as will upgrading your plenum.

PI head swap is not the same as headers. PI = Perfomance improvement. What the PI head swap is, is that Pre 99's have crappy *** restrictive heads, the PI heads are taken off a 01 GT called romeo heads which are much less restrictive and smoother. You can gain anywhere from 60-120 hp just off the PI head swap.

As for the exhaust. Those are all different parts your talking about. You have your headers then comes your mid pipe then comes your catback. Cats are short for Catalytic Converters. They are used to burn off any extra exhaust liquid. They are what makes it so that you pass emissions. Catback is everything from the cats back. Which is basically just your mufflers and your tips. So when you buy a catback you are buying the mufflers and the tips. X and H pipes are your mid pipes. The X is in the shape of an X the H is in the shape of an H. The X is better for top end perfomance and gives you more of a high pitched raspy sound. The H is better for low end torque and will give you more of a deep grumble sound.

I think 4.10 gears are better but not in your case. If you make alot of long trips you will definetely see a difference in your gas mileage. Even with the 3.73's you will see a difference. If you make long trips I would do some other stuff first before you swap out your gears. Get a manual dont get an automatic. Especially if you are going to make long trips you will get better gas mileage with the manual then you will with the auto plus the manual is much more fun to drive. Only time a manual sucks is in stop and go traffic.

It probably is possible for you to get 300 rwhp on the N/A engine but its gonna take some money. The PI head swap is a must if you are going for 300 rwhp on a N/A pre 99 GT. If u got the money for the PI head swap do that first or else go for some smaller mods first. Hope all this helps you out.

deesgt

As far as the trip, I make it twice a year. Is that still too much to change gears? So can I just buy an H pipe and a catback system and use the stock cats? My very first mod is gonna be a K&N intake. It's pretty affordable and it's something I can do myself to sorta get familiar with my car. I think I'm gonna start out with helping the car breath better. Then I'll go for the PI head swap. If I can figure this gear thing out then I'll sneak that in between. There's a guy here in St. Louis who does alot of people's Mustang gears. You buy the stuff and he'll do it for $150 and let you watch and/or help a bit. Thanks again for the info it really did help.

Razor19

Twice a year aint that bad you could do the gear swap if you wanted. The catback has like nothin to do with your cats. There are 3 kinds of H-pipes you can buy. There is the stock one, a high flow one, and an O/R one. Stock one has 6 cats, High flow has either 1 or 2 cats, and O/R has 0 cats. All of those H-pipes except the O/R will come with the cats. Just look around the forum you will find some CAI discussions on here. Its pretty much been concluded that Densecharger CAI will give you the best performance gains.

04mustang

i would just get the 99 to take care of the PI swap and alot of other small stuff that wrong with the 98. there is a big diff between the two and i think you will save more money buying a 99. if you have the money to fork out for a PI swap than you could pay a lil more for a 99. i murdered a 98 last month he had pulleys, midpipe, flows,shifter, and i killed him. get a 99 im my opinion. but if u really want a 98 than what razor is saying is all correct.

Razor19

Yea if u can get a 99+ definetely get that over the 96-98. Personally I like the look of the 99+ better also and they perform better. If u do get the PI head swap you will be running a little bit faster than the 99+ because you will be running a higher compression so thats one good thing. If you have the opportunity to choose though definetely get the 99+.