How much power can a 94 GT make if you don't change the look of the engine?

bennylava

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I'm thinking about rebuilding the worn out 302 in my 1994 Mustang GT. But I wanted to do something a bit different. A sleeper engine. That would mean making the factory engine as powerful as it can be. But look untouched, by all outward appearances. So how much power can the 1994 GT engine really make?

You'd have to have the intake extrude honed of course. Everybody replaces those intakes with GT 40 or Cobra intakes. But we can't do that here, so extrude honing it is. Next you'd of course do everything to the heads. That would be port and polish, lighter valves. a bit stiffer springs, etc. But is there any point in boring and stroking the engine? Remember we're forced to use modified factory heads and intake. So would you be able to get enough fuel and air in to take advantage of the bore/stroke?

You wouldn't want the cam to sound all that much different either. After all this is something of a sleeper build. But maybe a better crank, rods, and higher compression pistons could be used. You could use bigger injectors as long as they didn't look like bigger injectors. Same for everything else. So port out the throttle body to maximum, and do whatever you can with the factory air tubing that connects to it.

So how much power could you make this way? How much could be squeezed out of the 94 GT engine if it had to look stock?
 
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Bullitt347

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Or just leave it stock completely stock and put a 300hp Nitrous kit on it. It is a ton cheaper, takes a lot less work and accomplishes your goal.
 
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General karthief

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Ok Benny, what are YOU trying to do, run in a class or just hiding horse power?
If you're hiding HP a nitrous kit hidden under the intake would be the least expensive, if you go down the 'modified stock parts' route that's a bunch of money for very little gain.
A 'poke and stroke' with stock intake/throttle body and stock head modifications is still limited to low air flow numbers, a custom cam grind would help but to what end?
There is a drag class called Factory Appearing Stock Tire (FAST) but I believe they are limited to 60s/70s cars
I could be wrong. It happened once before :jester:
 

bird_dog0347

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I agree with General, what are you trying to accomplish? Tell us your goals, requirements, and any known roadblocks... then we can help you come up with a solution.
 

Mustang5L5

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Work over a set of GT40 heads, send the stock intake to Big Dogs/Tmoss for some porting, run a 85-88 HO cam with 1.7 RRs which I think some will fit under the stock valve covers.

Back in the day “Thumper” was a guy who would port stock iron heads and get good numbers from them.
 

bennylava

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The stock 5.0 block in that car can take about 500hp before you risk splitting the lower end in half.

I may be wrong about the application, but I believe a stud girdle can be purchased to strengthen up the bottom end. The block can be heavily modified, as long as it can't really be seen by an outward inspection. So it could even be a racing block (was it DSS brand?) as long is it appeared to be stock when it was installed in the car.

Work over a set of GT40 heads, send the stock intake to Big Dogs/Tmoss for some porting, run a 85-88 HO cam with 1.7 RRs which I think some will fit under the stock valve covers.

Back in the day “Thumper” was a guy who would port stock iron heads and get good numbers from them.

Do the GT40 heads look just like the factory e86 heads that came on the 94 GT? I may be wrong, but I was thinking they were aluminum heads. I suppose I could paint them black or whatever the factory color was, IF they look like stock heads once the valve covers are installed. But they must look stock. If they've got any casting marks or numbers or otherwise look different, I don't want to use them. Do you happen to remember how much power Thumper would make on the stock heads? Did he build anything similar to what I'm talking about?

As for the NOS idea, two problems: 1. Looking around, anyone can find it. Just peek under the intake, or look for extra lines. They gotta get to the engine somewhere. You should also be able to tell if you race the car and it's running nitrous. 2. It shortens the lifespan of the engine, and I don't like that. I like my engines to last a pretty long time. That's just my way, I want long life out of all my engines. An NA sleeper engine could do that, whereas nitrous couldn't.

As for why I'm doing it, this isn't a racing or qualifying thing, it's all just a want. Just building a sleeper engine. But the requirements are strict. If I start making exceptions then I may as well not even bother cause anyone will be able to see that it's not much of a "sleeper". So the rule is, nobody can tell by looking at the outside of the engine. It all has to look like OEM.

I would have loved to have such an engine back when I was a teen. I had a 94 GT back when the LS cars still new and were all the rage. Being able to hang with them or beat some of them with an engine that looked stock would have been a lot of fun. Not to mention really funny. I still know a few of those guys, and some of them even still have LS cars. If I plop in a coyote they can expect to get beat. But if I say "You know, these old engines were faster than people thought. We could race just for fun". They'll laugh. Then their car either loses, or they don't win by nearly as much as they thought they would. But really this is all just for fun.

Somebody mentioned goals, requirements, and known roadblocks. The goal is as stated, a power maximized stock looking engine. It also can't sound like a monster, because that would be a dead giveaway. I think we can allow for a little bit of non-factory noise though, because you can always just say "Oh yeah I put some flowmasters on it". Everyone expects some mild exhaust sounds (at the very least) from a Mustang. They'll still be fooled if the engine looks factory. The requirements are pretty well laid out by now, and I'm not really away of any roadblocks. When I do this (roughly 1.5 years from now) I won't be all that concerned about the money. The car's engine has 220k miles on it and it needs to be rebuilt. Not to mention I want a more powerful engine so the car will be more fun. So I already expect to be spending money.

Well, there is one possible hurdle. If you're familiar with the factory 94 headers, they're very restrictive. And they have a certain look to them. For some strange reason they're dimpled in, near the heads. Anyone who really knows what these engines look like, would spot non-factory headers cause no other header would be built with those restrictive dimples. But maybe I can still fool them by using slightly bigger headers that have the dimples. Again it doesn't actually have to be stock parts. Just hast to look that way and be convincing.
 

bird_dog0347

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First off I would say build the short block as a stroker engine, that will maximize the capabilities while maintaining a stock appearance outwardly. Next up is the heads, the only casting differences on the outside between the E7 heads and the iron GT-40's is the number of vertical bars cast into the front (of the engine) of the heads. The E7's have 2 vertical bars, the GT40's have 3 vertical bars, and the GT40P (explorer) have 4 vertical bars. The GT40P will also require the ford motorsport shorty headers to fit properly and not have spark plug/boot issues. A set of Ported 3 bar GT40s are going to work best for you if you're willing to let that one thing slide. Assuming you are keeping power steering, AC, alternator, and all factory looking stuff anyway, they will be VERY difficult to spot the differences on once it's in the engine bay. Go look at the front of your heads as they are now and tell us how difficult it is to spot the 2 vertical bars... worst case you could grind off the extras and paint them. They will also work with the stock valve covers.

As for headers, you mentioned the crappy stock ones, you really don't want to keep those as they will certainly be a big bottle neck... you also mentioned that people expect exhaust work to be done, so you could easily get away with just a set of shorty headers and say that's all that changed. You could also likely get away with an explorer throttle body as it's a stock ford unit, just a bit larger (65mm I think).

For the cam, I'd say contact a custom cam company, someone like Flowtech Induction, and give them your goals and requirements and tell them you want as much as possible while still sounding like a stock cam.
 

rednotch

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Probably around 320ish to the wheels.... The stock 94 95 intake sucks and would require a ton of cutting and welding then even more hours to make it look stock iron head head porting going to costly too.. Not worth it unless you can do your own work or want to drop thousands in labor.
 

nickyb

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you can hide nitrous with vaucum lines and wire wrap/tubing. get a dart block,gt40 heads and intake,oh dont forget to order a new trans. your gonna need one.
 
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7991LXnSHO

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Probably around 320ish to the wheels.... The stock 94 95 intake sucks and would require a ton of cutting and welding then even more hours to make it look stock iron head head porting going to costly too.. Not worth it unless you can do your own work or want to drop thousands in labor.
I have time slips with ported E-7 heads and ported stock intake, but a FMS cam and BBK headers on a ‘91 that calculates out 325-350 Hp. I had an extra set of heads and intake that came with the car (for their next backup engine), and they were ported A Lot. That’s more power than it should make, and I plan on going with a stroker kit after I wear this one out.
It can be done, but GT-40 heads already flow better, so any porting will already put you ahead. Grinding off the third bar would be worth that head start.

And, @General karthief, the Po’s team were running my car in some stock tire and appearance class, got irritated at the computer, (no emissions stuff and bad capacitors in the ECU) and went to a 60’s Barracuda. I should have gotten more info on the class or series.
 
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Monkeybutt2000

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i built a similar engine over 20yrs ago. 306ci with stock GT40 heads,Cobra intake,stock cam 65mm TB and all the normal bolt ons. Went 12.80s @105mph. It was built for the now defunct FFW Factory Stock class.
 
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rednotch

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I have time slips with ported E-7 heads and ported stock intake, but a FMS cam and BBK headers on a ‘91 that calculates out 325-350 Hp. I had an extra set of heads and intake that came with the car (for their next backup engine), and they were ported A Lot. That’s more power than it should make, and I plan on going with a stroker kit after I wear this one out.
It can be done, but GT-40 heads already flow better, so any porting will already put you ahead. Grinding off the third bar would be worth that head start.

And, @General karthief, the Po’s team were running my car in some stock tire and appearance class, got irritated at the computer, (no emissions stuff and bad capacitors in the ECU) and went to a 60’s Barracuda. I should have gotten more info on the class or series.
Ok??? Thats not what op asked, or what I replied to. he asked about power while looking bone stock, that means a fully dressed engine to me. .....He asked about power on modified stock parts so E7 heads and a production 94-95 gt intake, induction and stock looking headers, that's pretty much a cheated up h/s, I/s class engine but fully dressed with accessories.... so about 320ish to the tire with alot of money dumped into labor cutting and welding parts and making them look untouched, that aint cheap and definitely not worth it when your not building something to class rules..

I've seen e7 headed cars run 10's on motor and 9s on a small shot of nitrous, but its not what he's asking about. An over geared class car or a tin can track toy with junkyard parts looks nothing like "factory stock" like the op stipulated, I never said you cant go fast with those parts.
 

TOOLOW91

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This is going to cost a lot of money to make subpar power .

I can’t see building a stroker - not being able to move enough air to take advantage of the whole package .

Gt40 heads are steel . I’d use them If anything have the 3 bumps shaved off or down . Ported that will make way more power then any ported e7 could . Then use a explorer gt40 intake with a 87-93 mustang plaque on it . It will look the closest to stock . Then use whatever choice of mildest camshaft you can find or a stock cam with 1.7rr .

Then hope it maybe makes 300 at the tire .

You won’t need any type of stud girdles or anything like that . If it is is purely to race your friends who are ls guys . Odds are most of them wouldn’t know the difference of what they are looking at with the factory ford parts . You could even use a set of 93 cobra unmarked valve covers to not worry about rockers fitting and appear factory. Depends on how far you want to take it.

Lot of money here for a small reward .
 
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bird_dog0347

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This is going to cost a lot of money to make subpar power .

I can’t see building a stroker - not being able to move enough air to take advantage of the whole package .

Gt40 heads are steel . I’d use them If anything have the 3 bumps shaved off or down . Ported that will make way more power then any ported e7 could . Then use a explorer gt40 intake with a 87-93 mustang plaque on it . It will look the closest to stock . Then use whatever choice of mildest camshaft you can find or a stock cam with 1.7rr .

Then hope it maybe makes 300 at the tire .

You won’t need any type of stud girdles or anything like that . If it is is purely to race your friends who are ls guys . Odds are most of them wouldn’t know the difference of what they are looking at with the factory ford parts . You could even use a set of 93 cobra unmarked valve covers to not worry about rockers fitting and appear factory. Depends on how far you want to take it.

Lot of money here for a small reward .
I was really hoping this was something to do with emissions or laws, or class rules... but I must confess I am disappointed that we are giving advice on how to beat a 350Z bone stock after spending 10k + dollars for no benefit that I can see other than being able to tell the other driver you beat them on talent alone *when you didn't*.

Then again, to each his own!
 

bennylava

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First off I would say build the short block as a stroker engine, that will maximize the capabilities while maintaining a stock appearance outwardly. Next up is the heads, the only casting differences on the outside between the E7 heads and the iron GT-40's is the number of vertical bars cast into the front (of the engine) of the heads. The E7's have 2 vertical bars, the GT40's have 3 vertical bars, and the GT40P (explorer) have 4 vertical bars. The GT40P will also require the ford motorsport shorty headers to fit properly and not have spark plug/boot issues. A set of Ported 3 bar GT40s are going to work best for you if you're willing to let that one thing slide. Assuming you are keeping power steering, AC, alternator, and all factory looking stuff anyway, they will be VERY difficult to spot the differences on once it's in the engine bay. Go look at the front of your heads as they are now and tell us how difficult it is to spot the 2 vertical bars... worst case you could grind off the extras and paint them. They will also work with the stock valve covers.

As for headers, you mentioned the crappy stock ones, you really don't want to keep those as they will certainly be a big bottle neck... you also mentioned that people expect exhaust work to be done, so you could easily get away with just a set of shorty headers and say that's all that changed. You could also likely get away with an explorer throttle body as it's a stock ford unit, just a bit larger (65mm I think).

For the cam, I'd say contact a custom cam company, someone like Flowtech Induction, and give them your goals and requirements and tell them you want as much as possible while still sounding like a stock cam.

So:
1. Custom ground cam that goes right to the edge of stock road manners.
2. Stock block bored and stroked (unless you can't tell a DSS block from stock?)
3. Maxed out e7's or slightly upgraded GT40's with a bar ground off so they'll look just like e7 heads.
4. The intake worked over 6 ways from sunday
5. Throttle body ported out to maximum
6. Some kind of headers that look as close to stock as possible, but slightly larger and without that awful indention ford put in there. I might even be able to put some kind of optical illusion on the headers, so it vaguely looks like that indention is there. Yes, I am a nut. Yes I will do it. IF it would work out and function as intended. Probably involve a little ceramic coating artwork of some kind.
7. A high end, full exhaust system with flowmaster hushpower mufflers. They're quiet but they're almost a straight pass-thru. Leave those factory tips sticking out the back to help complete the illusion. Anywhere the new tubing can be seen, paint it brown-ish or get it dirty enough.
9. Aluminum driveshaft? Paint it black
10. Other odds and ends?... Such as a lightweight racing flywheel? To squeeze out every last bit. ?? Anything else that can go on this list?


I will be putting all the factory engine accessories back on, yes. I'm not losing my AC, and I do need everything to help me obscure stuff.

you can hide nitrous with vaucum lines and wire wrap/tubing. get a dart block,gt40 heads and intake,oh dont forget to order a new trans. your gonna need one.

Would a dart block look different than the stock block, from the outside? Can't use GT40 intake, has to be stock. The trans can be something else, it's too hard to tell what it is. Just needs to be a 5-speed cause that's what the care came with. Maybe build up a T-5


I was really hoping this was something to do with emissions or laws, or class rules... but I must confess I am disappointed that we are giving advice on how to beat a 350Z bone stock after spending 10k + dollars for no benefit that I can see other than being able to tell the other driver you beat them on talent alone *when you didn't*.

Then again, to each his own!

Sir, you sorely underestimate my desire to troll. :jester:

I guess some people don't appreciate the fun associated with the word "sleeper". But erm, you really hoped there was some kind of law? Most people I know hope for less laws lol. And if these power numbers are close to accurate, it seems like you'd be able to beat more than a mere 350z by doing this. Your typical LS trans am or camaro put what... 320 to the wheels? If he's right this would put the car somewhere near 390 to the wheels. That would be enough to beat all those old LS cars if they were stock. Maybe not by much, but still. And there will be some skill involved, because I've always wanted to get some training and I intend to. Imagine how badly you'd beat them with a 390hp car AND some skill.

Lastly, I have several friends who would think the car is slow. I could show them the engine, and say "Look I cleaned the engine really well! But eh, it's just a stock'er. Want to take it for a spin?" Many of them will say yes because the car looks really clean inside and out. They might want to go down memory lane, or just have fun driving a mustang for a bit when usually all they drive is family-mobiles. Then look out! It's a beast they didn't expect. The whole thing will be pretty funny.

Say "Yeah back in the day these cars would often beat the LS cars. What you're remembering, is cars that just had engine problems, or were perhaps old and worn out. You never know, they might have had a whole lot of miles on their engine, when facing a new camaro with low mileage. And how many races against these did you actually see? And do you really remember what their times were? That was a long time ago. This one just runs like it's supposed to because as you can see, the odometer only has 30k miles on it." ... Say all that with a big grin and trying not to laugh
 

General karthief

wonder how much it would cost to ship you a pair
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That LS in the race likely ain't stock anyway.
I'm thinking this is a giant waste of time/money, I can appreciate the thought but realistically your gonna get gapped by a V6 toyota family-mobile with a high school kid with pimples driving it.
 
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bird_dog0347

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Sir, you sorely underestimate my desire to troll. :jester:

I guess some people don't appreciate the fun associated with the word "sleeper". But erm, you really hoped there was some kind of law? Most people I know hope for less laws lol. And if these power numbers are close to accurate, it seems like you'd be able to beat more than a mere 350z by doing this. Your typical LS trans am or camaro put what... 320 to the wheels? If he's right this would put the car somewhere near 390 to the wheels. That would be enough to beat all those old LS cars if they were stock. Maybe not by much, but still. And there will be some skill involved, because I've always wanted to get some training and I intend to. Imagine how badly you'd beat them with a 390hp car AND some skill.
To the first point, no I do not hope there are laws against it at all... I was hoping that you were forced into making these choices due to some dumbass law, not because you want to troll. If what other people think, even when they are lied to, is worth thousands of dollars to you then hey... it's your money! Do as you please!

To the second point in bold, there is precisely a 0.0% chance of making anywhere close to 390 to the wheels with the combo you've listed. You will be extremely lucky to squeeze 290 to the wheels out of that. The 94 is also heavier than a fox, likely by 4-500 pounds and each 100 pounds would be worth roughly a 1/10th in a quarter mile... good luck getting a few hundred pounds out of it and looking stock.

I really hope you're able to meet your goals, and I'm not trying to be Debbie downer over here, just trying to help you make good choices with your money.