Expected gains from mods

[Big Dooker]

Can someone tell me what kind of HP Gains I could get from the following mods to stock '98 Cobra?
*Headers (what is the difference between shorties and long tube headers)
*X Pipe (with cats) or without the cats--Ohio just dropped their EPA check
*Hi-flow exhaust
*K & N Filtercharger
*New MAF sensor (what do you recommend?)
*Performance chip

I'm trying to get north of 350HP without digging into the engine and affecting
reliability and driveability. Are there any other mods anyone could recommend? I want to keep it cost effective, so I don't want to go with a supercharger at this point.

Any help or recommendations are appreciated!

 

[greenstang1313]

i don't know TOO much about the DOHC 4.6 motors but the mods you listed should get you to about 290 rear wheel horsepower, or about 335 horsepower at the engine. If your looking to put 350 to the wheels, you can expect to start going into the engine.

 

[blkstangman88]

to reach even 290rwhp u better have fresh plugs wires and IMRC plates cleaned and shiny. personaly id be more concerened about upgrading suspension and drivetrain b4 worring about hp ratings. gears, tranny, and suspension items first... my .02

tips, dyno tune with a custom chip, march U/D pullys w/sfi, CAI doesnt do much but looks kol, some will recommend an electric water pump, plug it into a relay and the car will warn u if it fails. plenty more just cant think right now

 

[SVT98Snake]

to reach even 290rwhp u better have fresh plugs wires and IMRC plates cleaned and shiny. personaly id be more concerened about upgrading suspension and drivetrain b4 worring about hp ratings. gears, tranny, and suspension items first... my .02

tips, dyno tune with a custom chip, march U/D pullys w/sfi, CAI doesnt do much but looks kol, some will recommend an electric water pump, plug it into a relay and the car will warn u if it fails. plenty more just cant think right now

??

290 is very doable in the 4.6 b headed cars.

I made 293 with headers, exhaust, pulleys, JLT, SCT, and dirty IMRC's.

 

[blkstangman88]

personaly i just dont get my hopes up till i get the dyno chart. id reather under guess it then over. yes theres TONS of potential with these cars, ive just heard of to many ppl being disapointed so i was just saying..

 

[SVT98Snake]

I will agree with you on that....the 96-98's are not as responsive to mods as the 99+ cars are. The head and intake design is totally different and more responsive in those.

I made 274 with a cat back only....I only gained 7 hp with the rest of my mods until I put my headers on....after that and a full re-tune, tb, and mass air, I made 304