That is really optimistic, even with a 5.4 liter, that would be still a slightly optimistic. I'm thinking if you are not doing the all of the work your-self then a supercharger of some kind would be more economical.
Trickflow is the way togo...but the have a heay price. If I were on a budget i would do PI's with comp 268 or 270 cams and long tubes, some kind of upper 75mm intake and tb, pulleys, and maybe an electric water pump. That would put you around 270+rwhp. you'll need 24lb injector or more with a good tune
Yeah, as others have said your best option for a N/A combo is 38 CC TFS heads with cams (13:1 comp), headers, etc... that would net 320+ RWHP, but honestly for the kind of money and time required to make that kind of power why not piece together a Vortech kit?
You could likely piece together a vortech kit for $3500 including everything and make 380+ RWHP.
A guy my car club has a 96 Mustang with a WAP alum block, TFS heads, Bullitt intake manifold, and MHS stage 2 blower cams. He set it up for boost (9:1 comp) and laid down only 262 RWHP through the stock cast iron manifolds. I was able to get 240 RWHP by installing MHS stage 2 NPI N/A cams. The point I'm trying to make here is that based on what I've read on these forums, I believe people have been overstating/exaggerating 2V dyno numbers for years. Depending on the dyno type, it will also play into your numbers. I'd likely make over 265 RWHP on a Dynojet with my car, yet it only made 237 RWHP on a dyno dynamics unit.
I'm really more curious about what your goals are for the car you have. If you want a fun DD, then PI heads and cams will do that no problem, if you want to tear up the track then I'd suggest a vortech kit. The last thing I want to say is that a dyno is nothing more than a tuning tool, what you do at the track is what really matters.
ok ill just say youll make a good amount of power with head/cams swap an it wouldn't cost that much... The vortech set up would make more power and done the right way would cost more but that wasnt the original question.
Ive built 400rwhp SAE 96 with 04 explorer engine (WAP), s-trim, watermeth.. It ran 121mph in the quater full weight
My trick flow 38cc, TF stage 2 cams , jlt intake, 75 upper and tb.. ran 111.42 in the quarter full weight Convertable
ive built 04 cobra 813rwhp 2.9 crusher, cams, headers.....taken it easy on it ran 140 in the quarter full weight
I could go on... my point is I know a pi head stage 2 cam car in a 5 speed will put down 260-280rwhp sae Ive put this set up on 10+mustags/t-birds. Thats all im going to say about that.