If you want to make power N/A then you probably don't want to use B heads. Your 96 manifold won't work with other heads. Only B's. Making power up to 8k will require some wild cams which will mostly likely kill any power below 4k. So I wouldn't worry about making power in the lower rpms. FR500 intake or if on a budget get a 99 intake and make it into a shortrunner. -Mark

 

The high compression will help solidly with low RPM. I'm looking for a relatively flat torque line from down low to the top. If it makes 280 torque at 3000, peaks around 340 at 6000 and carries out to 8500 with 300, I'll be unbelievably happy. A well designed manifold can do that.

The '99-01 Cobra manifold is a piece of garbage to start with compared to the '96 Manifold or the FR500. The end runners are hugely compromised for air flow due to packaging, and there is no volume left in the plenum after you convert it to a short runner. The plenum cover has no volume to it, so if you lose th bottom part of the manifold in converting it to a short runner, you have no plenum volume.

The '96 upper has substantial volue on it's side. With the runners removed and replaced with air horns, this manifold has a ton of potential , it will just require a tremendous amount of work. With respect to fitting the '96 manifold to '99+ heads. Also, I have the Continental B to C adapters as well, which buy me a huge advantage in starting the conversion. I can bolt the spacer to the head, port it to match the head, then bolt the spacer to the manifold and port to match. The big work with these spacers is going to be getting rid of the split in the ports and making the manifold and spacers a single port the entire way through.

I'm estimating 80-100 hours to make the '96 Manifold work the way I want it to on the C stye heads. While my time is technically free to me, I could use that time to make money that would buy a proper manifold too.

So my big question still remains, are ther any other options out there?

 

I'm not sure if you are talking crank HP or RWHP.
If you are looking at RWHP I think you should do as much research into the Roush/Yates DP program as you can. Their engines run somewhere north of 600 crank HP and appear to be a competitive package.
I have spent a fair amount of time talking with them at the track and at PRI about how they build them. They started out using ported 03 cobra heads, the FR500 manifold, and cams that they wouldn't tell me a thing about.
After that they started using the GT heads and their own manifold.
We make VERY competitive power out of our 4 valve Pure Street motors that with some minor changes (throw the rule book out) could put you in that HP range also.

Give me a call if you want some more details.

Greg

 

I'm talking rear wheel power. This would put me in the 475+ range for rwhp and probably around 550-570 flywheel.

There is no rule book to worry about right now for the intended class. It's fairly open. The only time I would need to look at rules is if I start thinking AIX

 

There is no rule book to worry about right now for the intended class. It's fairly open. The only time I would need to look at rules is if I start thinking AIX

You don't need to look at a rule book for AIX.
Anything but Nitrous is legal on the motor.
What class do you plan to run the car in?

Greg

 

Your best bet is to mirror Nazman's setup. He made 478ish to the tire. But its not cheap. Do a search for stang32v. That's him. -Mark

 

That was with a Big Bore....quite a bit more with the Big Bore/Stroker!

 

Well, I would not delete the Sullivan option.

I made over 40+RWTQ from ~4000RPMs up (true with an extra 18CIs [304 vs. 322]) than a FR500 intake in LONG runner configuration with the Sullivan intake.

My trottle response was nothing but spectacular and pulled all the way to 7750RPMs and wanted to keep going.

This was with my own ported heads and custom cams. The cams were big but nothing extremly wild. Only the lift was a little more than your standard "aftermarket" cams at .500 lift. That combo was good for 128+MPH in the 1/4 mile @ 3350LBS car.

So, a similar combo with billet rods, a little more duration (move the power band up a tad) will rev to 8000+RPMs and make even more power.

Naz

 

At this point in time, the plan is to keep the displacement near stock. It will be .020" or .030" over and stock stroke. Later, I want to build a big bore motor with a FRPP block. I prefer the idea of the dedicated block over sleeves. If I do go with a big bore motor, I'll probably shorten the stroke a little to fit a slightly longer rod. Something like a 6.125 rod on a 3.400 stroke and a 1.1xx pin height and about 14:1 compression. But that will be a $10k shortblock, and I can't justify that expense until the rest of the car is complete and has a couple events under it.

 

I say good luck. You want to make 550-575 hp on 281 ci. That is asking ALOT. Naz made a killer motor with the Sully. But, if you are against the Sully, why don't you make your own intake? If plenum volume is a problem on the 99+ intake, you could always fab a spacer for that, but I still think that intake is a limit to how high you wanna spin. Personally, I'd for get the GT heads, get 03/04 heads and spend the difference on a BB-stroker. You have a much better chance of getting what you want power wise.

 

Thing of it is, for my purposes, I need rpm, not brute torque. The right manifold, cams, and heads will allow that, regardless of the cubic inches in place. Now, a bigger bore will certainly make more power, if only for the fact the larger bore unshrouds the intake valves allowing the head to flow more. Displacement is very much secondary in my case., and in reality, the way I plan to eventually build the short block, it will make equal torque to the longer stroke, smaller bore shortblock I'm starting with.

Case in point, I have a motor in my current track car that has too much stroke. It's an 88mm bore and a 94mm stroke DOHC 4-cylinder Ford. There is an 83mm stroke available. With the shorter stroke, you have to turn about 600-800rpm more to get the same horsepower. The difference is you have less torque, and that is actually ok for what I'm doing. In that car (FWD) too much torque just spins the tires coming out of the slow turns. Even with a torque biasing diff, it's tough to get the power down. I'd be thrilled to trade 10% in torque for 10% more rpm, at the same peak horsepower, and that's about where it would land with the crankshaft change.

This isn't my first rodeo. I appreciate the concerns that I need more displacement, but thats not what this post was about. I'm just exploring intake manifold options.

 

Well, for right now the car is going to be an occasionaly street driven Time Trial / Time Attack car out here on the West Coast. I'm having a full cage installed. I'll be doing some interesting tweaks to the 04 IRS I have installed under the car. I'll be running a hand picked gear set in a 6-speed with a lot of rear gear. I may have a line on an affordable set of complete GT-500 heads. All things point to completion by next summer.

I really don't have to play by any rules. If I run NASA TT I'll just be up against turbo Porsches and such. The other venue, well, the rules are so vague that I intend to "cheat" them out of an event win using their own rules against them.

Greg, I'll try and give you a call at some point.

 

You'll have to spin the crap out of the motor to make the kinda power you want. Also, reliability goes to crap at rpms in the 8500 range since the piston to valve clearance is minimal at best.

The 96-98 intake stinks in any configuration and especially with the runners removed. You'd be looking at an intake good for 10k and above if you do that.

The 99/01 and Mach intakes perform expremely well when made into short runners and despite popular belief have more than enough plenum area when a spacer is added. Combine one with some well spec'd cams and the motor will make decent torque and plenty of hp. I know of one that made 500rwhp. One last comment about plenum volume, the stock 99/01 intake when made into a short runner has as much plenum volume as an FR500 intake in short runner form and it works damn good.

The ports of the GT heads are way too large for a stock bore/stroke motor as are the Navis. Stick with the FR500s or 03/04s.

One last thing, there is no reason to shorten the stroke to run a longer rod.

 

http://www.musclemustangfastfords.com/tech/mmfp_0803_2007_sema_show/photo_28.html Build a box around it with a removable top + oval t.b. + maf. You could then play with the runner length easy. editing

 

This is going to be a high compression track motor with really good parts llike a lightened crank, billet rods, smaller pins, etc. 8500-9000 rpm are well within the build parameters. And much the same as when you under cam a stroker motor, if the heads are too small, the engine won't rev. The GT heads and big cams are to support the rpm.

This is not going to be a run of the mill poor mans build. It's not my first race motor.

I may have a line on a worthy manifold, If I get it' I'l post pictures.. I may also be finishing my short runner anyway for a buddies car. I'l post a before and after dyno when that one is done.

 

And much the same as when you under cam a stroker motor, if the heads are too small, the engine won't rev. The GT heads and big cams are to support the rpm.

I know what it takes and the GT heads are still too much for a 281ci motor. Also, an intake for 03/04 heads will not work on a 4.6 with GT heads.

 

Based on your intended use, sounds to me like you'd want this:

Karkraft is selling this (used) engine, and it can be found HERE.

This engine is purpose-built for the type of racing you do. :salute:

It would seem to be a worthwhile option rather than trying to piece-together a combo on your own.

Good luck finding one of these intakes for sale seperately though... :crying:

 

Based on your intended use, sounds to me like you'd want this:

Karkraft is selling this (used) engine, and it can be found HERE.

This engine is purpose-built for the type of racing you do. :salute:

It would seem to be a worthwhile option rather than trying to piece-together a combo on your own.

Good luck finding one of these intakes for sale seperately though... :crying:

Well, I don't have the funds to lump into one of thse motors, even a used one. And I'm planning on making more power than they are rated at, so I'd have to spend even more on it after I got it. That simply doesn't make good sense to me. That manifold would be incredible if it wasn't cast from unobtanium.

 

i would build your own intake for your intended purpose. that is the only way you can get it to work right for your combo. no off the shelf intake will work the best.

 

The info I have seen rates that engine at 400-450+/- flywheel. Not nearly what I'm looking for. It's only 11:1 compression, I plan on running 12.5:1. The pistons and the cams would have to be changed, which is going to be a $2500 expense right there with the gaskets and balancing. If I'm going to spend that, I might as well do it on my own engine, because it's not like I'l have people standing in line offering top dollar for the old parts. I'm going to have well over $10K in the stock bore motor over a course of a year. I only paid $2500 for the car.

And I'm honestly growing tired of hearing that the GT head is the wrong way to go. My 138 cubic inch 4-cylinder race motor had a head that flowed over 300 cfm at .450" lift. The port was fairly stock, the only work was in the bowl and a very trick valve job. The exhaust side of the head received a bit more work and the port was opened up to the 1-3/4" header. That car was beyond potent.

I'm using the same build approach here. The GT heads will not get any larger from porting, but they will see a little intake bowl work, and the exhaust side will get bowl and roof work. The valve job will bring it all together. When I'm done, I expect to make nearly 500whp from a stock bore motor. As much as everyone will call it a pipe dream. The fact is, my 4-cylinder race motor made 240whp with less than half the displacement and less than 7500rpm.

I'm going to procede with the project. The more I hear it can't be done, the more motivated I get.

 

And I'm honestly growing tired of hearing that the GT head is the wrong way to go. My 138 cubic inch 4-cylinder race motor had a head that flowed over 300 cfm at .450" lift. The port was fairly stock, the only work was in the bowl and a very trick valve job. The exhaust side of the head received a bit more work and the port was opened up to the 1-3/4" header. That car was beyond potent.

It's not about how much (CFM) the GT heads flow, it's about the velocity of the charge and with only 281 cubic inches the charge velocity will be very slow. For example, I know of a 281 ci motor that made peak power at 8500rpm with extensively C heads. Replacing those heads with C heads that have smaller intake ports (not opened up as much) resulted in more hp and tq but the peak power occured at the same rpm.

 

I'm glad to see that you are still going to try. I hope it works out for you. Did you decide on an intake? Keep us posted with pics and numbers as you get them

 

I just threw the FR500C intake/engine out there as an option because it seemed suitable for your needs.

That + the fact that there's so few intake manifolds available for the 4.6 4V

Guess I was wrong...

 

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There is no way I'd spend 10x what I paid for the car on a motor that didn't meet my specifications. I'm looking for closer to 500rwhp and with some of the research I've done the past few days, that's a real possibility.

As I stated in an earlier post, I have a line on a worthy manifold through a good contact. He promises I won't be disappointed, but won't tell me any more than that. I should have more information soon, and I promise I'll share the info.


I've found some very cool valvetrain bits that no one advertises as fitting these engines. It turns out that with the amount of duration I want to run, the valve lift will require a higher installed height on the valve springs, and in turn, I found springs that are a perfect compliment to the planned combination. So the valvetrain may be fairly well sorted.

I have a piston manufacturer willing to make my pistons with domes and valve reliefs from my CAD files, a very cool deal there. Plus, they will make them with a smaller diameter narrower pin, cutting down the total piston weight without any loss of strength. It means if I run an off the shelf rod I'll end up putting a smaller bushing in the small end, but that I don't mind.

I'm shooting for having this thing up and running by next spring. So given where I'm at now, with what I have and What I need, things should come together pretty well.

 

As I stated in an earlier post, I have a line on a worthy manifold through a good contact. He promises I won't be disappointed, but won't tell me any more than that. I should have more information soon, and I promise I'll share the info.

The GT head's bolt pattern/port location is different from all other B heads. Will the intake you have in mind it fit GT heads?

I've found some very cool valvetrain bits that no one advertises as fitting these engines.

I know of three companies that make solid lash adjusters and upgraded followers for these motors, one is L&M and another is Jesel (can't remember the third). I've heard they make more power but have seen nothing about their reliability. You may want to check with one of the mod motro builders that has experience with 9k motor and these aftermarket valvetrain pieces.

It turns out that with the amount of duration I want to run, the valve lift will require a higher installed height on the valve springs, and in turn, I found springs that are a perfect compliment to the planned combination. So the valvetrain may be fairly well sorted.

How will the duration affect the lift lift you will be required to run? The lift should be determined by the flow capability of the heads and also the valvetrain's ability to control the valve's opening and closing at 9k. Also, your valvetrain geometry will be all jacked up if you run longer valve stems...especially if you use non-adjustable adjusters/followers.


The kinsler type manifold is the way to go and is proven to work and is very tunable...good choice.

 

As I stated in an earlier post, I have a line on a worthy manifold. Sheet metal?

 

Holy quadruple post! :lol:

 

http://www.kinsler.com/page--Ford--16.html The n/a h.p. list what is close to the top ? Joe Hutchins (475) 5.3L(SHM), Ported B head/Cams/Kinsler IR intake/RG. B Head HP Champion.