I have a 1998 V6 mustang with a single port. Would I be able to switch to the Dual Port that came on the 1999-2004's and if possible how much would it cost?

 

It is possible, but I cant remember what the estimated price on it was. Im thinkin its about 1500 or something in that area, but someone else will chime in with a closer guess if Im off.

 

1500 sounds about fair, new heads and at least a lower intake manifold if not upper and lower. keep an eye on the junk yard for crashed 99 and ups...but also, with a single port, you can pop on a S/C from a thunderbird? easier...think about it...

 

you can also look for 97 up f150s. i am pretty surethat is when they started to have split-port

 

f150s never had single port, they went to the 4.2 in 98 from the 300 I6

 

Yes you can, http://www.rpm-mustangs.com/ has all you need for the swap. If you get just a basic swap kit, the whole thing will cost around $800, if you get everything needed, and a little extra, it's around $1250 for the kit, if you go all out, and get a fully ported system, it's gonna be around $1800 (best buy). Not sure about any shop charges on install, so you should look into that, but if you know a little bit about cars, or know a mechanic, then I'd install it myself, just be prepared to have your car down for about a week for the swap.