everything works together, so it really isn't that simple; you won't get the full benefit of a new intake until you've replaced the heads and vice versa. that goes for pretty much every engine mod you can do.
with that said, new heads will make the biggest difference. of course, replacing the heads is much more expensive than the intake or the cam.
The usual progression, if you cant do all at once, is to uprade the upper/lower intake, with the MAM and TB. Now you have the front end taken care of. THis will give you some really noticeable gains. I agree if you want to change the cam, do it with the heads. Im still running stock heads and cam with my setup. I may change the heads eventually, but Im still deciding on whether I should do a cam.
On a stock car, I think you'll see more of a gain with the intake over heads. Heads are MUST DO, but on a stock car, I think the intake is your best bang for the buck. You won't notice much with alum heads on a stock cammed, stock intake car. AFR's website shows otherwise, but I'm not convinced.
The decision is simply one of economics. For proper upgrading all parts of the breathing system need changed, intake, heads, exhaust.
I just finished swaping/upgrading my 95 GT w/ Ford racing parts, aluminum heads, 1.7 roller rockers, GT-40 intake, 65mm throttle body, headers and exhaust. I did the suspension at the sametime and a huge difference. Set me back about $3000 total.
If $$ are tight start with the easy stuff, Intake, Throttle body, free flowing air cleaner and then move on with the rest as $$ permits. If money is real tight lok into the explorer intake. Not as good as the GT-40 but can be had at the junk yard.
PS, I used the 1.7 rollers because they give you about the same performance increase as a mild cam without having to tear apart the engine. Also, you can get the GT-40 iron heads a whole lot cheaper if you are not looking for the weight reduction.
I vote for saving up your money and doing it all at once. I'm a lazy butt, and I don't actually *like* to work on my car every other weekend . I went from 100% stock to the setup in my sig in three days. I noticed a difference .
I am saving my money to do all three at once. I just bought a 94-95 Cobra intake for $200 and now I am saving to buy a set of heads and a mild cam. Every forum I have looked every one said the intake is the best way to start. But I am like HairyCanary and I don't want to keep ripping apart my car every weekend. So I have a whole box full of stuff (intake, a couple msd boxs,TB and some other little things) that I am going to put on all at once.
Look at what Paul runs with a Performer! I remember reading on here about a guy in Florida with a vert that runs low 13's with GT-40 X heads, 2031 cam, and a Performer. Then he swapped on the RPM and actually lost time. He has the Performer back on his car now. The Performer is a perfect intake for a stock heads and cam car and even an aftermarket heads and cam car.
EDIT: BTW, I gained low end from doing the Performer on stock heads, cam, and MAF.
The Performer has some large runners (1.2"x~2.0"), but it narrows down in runner cross section as it approaches the head and this allows it to be used in applications similar to what the Cobra family would be used on and make similar power. I just ported a Performer to some AFR 165 heads and it will make some very good power there too.
The "CNC" port match to the upper is lacking though - it only extends into the lower intake about 1/4" where it narrows in cross section - not bad for a smallish-med flow head, but definately a place to improve as flow goes up.
There is an old 5.0 Mustang article about modding a 94 Mustang. With a stock intake they only saw 8rwhp with a set of Edelbrock Performer heads, I think you'd see more then that with an intake along, plus its easier to install.
WTF...I remember a guy in the 5.0 Tech forums that put on *just* a set of AFR's and had the car dyno'ed before and after. There was a gain of 40hp from the heads alone, on an otherwise stock motor. He also planned to install intake, cam, etc. but had the heads alone dyno'ed so that others would see the difference that AFR's make.
I just find it hard to believe that the car realized a 40hp gain with AFR's through a stock intake.
40hp? I hardly gained 40hp with all the mods in my sig. Is that the same car that AFR advertises on their website?
I can look up the article tonight if you want to see it. I posted the article a few months ago on this forum under the subject "old mustang articles". The car had a few other bolt-ons before the heads went on.
If you're going to swap out heads, you might as well swap out the cam as well since you're half way there.
Zen, the article was in a ~1998 issue of super fords magazine if memeory serves me right. It was a GREAT article where they dyno'd the car after EVERY single bolt-on, and I do remember them only getting <10hp. Heads are a great idea in terms of being there to support future goals for the car, but if I could only pick one... it'd be the intake.
Green95droptop is the guy mentioned about that switched from an RPM to a regular performer.