Need advice and oppinions from those of U who have been there done that

[SlideWaySTI]

I have a 1993 5.0 notch 5speed red on black. Looking to go turbo with an aftermarket longblock. Stuck with what cubic inch motor I should go with. I am thinking 331. My goal is to build a car that will run stronger than my previous car which was a MKIV Supra which made 631 RWHP. I want this car to run on pump gas 93 octane still have air and cruise. I am looking for a car that will be faster from 30mph to 150mph than the big bore motorcycles. Any advice on what cubic inch motor to use. Also reliability is a big concern too.

Possibilities

1. 331 DSS Level 20 AFR 205s T-67 turbo
2. 408 AFR 225s Turbo
3. 4.6 Teskid block forged internals turbo
4. 2003 cobra motor turbo or supercharged



Any advice or suggestions feel free to steer me in the right direction. My budget will be 12k for motor and i am undecided on what type of tranny to use.

 

[90mustangGT]

Since you are going to redo everything and go with an aftermarket block and all that how about stepping up to adult sized engines, do a Dart 9.5" deck (351Wspec) and stroke it to at least the high 300's if not somewhere in the 400's in displacement, then go from there. With a turbo and the cubes that kind of power is a walk in the park.

 

[FastDriver]

In terms of affordability, #4 is your best choice. In terms of accomplishing your objective of beating a Liter-plus bike on pump gas, the 408 is the only choice.

Take a look at my build thread. It's an example of a building a 331 to do what you want to do. However, don't even think of attempting it on a DSS331 unless you go with an aftermarket block. A level 20 will not make it to 700rwhp, and maybe not 600rwhp.

If you want to outrun the big bikes on pump gas, you're going to need more cubes than a 331. Mine put down 762rwhp at 6100rpm with 14 psi, and it was still climbing; it's rev limited at 7k rpm. I kept the tune conservative, and could've pushed the boost up, as well. Going over 800rwhp on pump with my combo is easily doable, but that still won't be enough for a big displacement bike like a hayabusa. They trap in the 150s, and you'd need 1k+ rwhp (manual tranny) to run like that. My combo should be capable of it, but only on race gas.

The reason I think #4 is the best choice of those you listed is the price. Those motors are stout and can take 800rwhp before you stress the internals. They have gone to 4-digit power levels with stock internals, too. I believe that even the 351 windsor block itself would have trouble lasting at those power levels. Some use block filler to strengthen them, but even then you've still got to do all of the internals and then grit your teeth when you really go for it.

Since you mentioned reliability, and price are concerns, #4 is the best option you listed.

 

[302GTS]

Since you are going to redo everything and go with an aftermarket block and all that how about stepping up to adult sized engines, do a Dart 9.5" deck (351Wspec) and stroke it to at least the high 300's if not somewhere in the 400's in displacement, then go from there. With a turbo and the cubes that kind of power is a walk in the park.

408w with a decent h/c/i combo with a nice 76mm turbo maybe? Big cubes really get along well with boost when it comes to the Mustang/domestic world. Imports may make great power with boost, but when you combine a hairdryer with a stroked SBF, you'll be scootin'!

 

[FastDriver]

No less than an 88mm turbo with a 408W, IMO.

 

[SlideWaySTI]

Yeah I really like the #4 option. What scares me about it is all the change over in wiring new ECU and getting everything to work. In the past this can become a nickel and dime nitemare. I was actually considering the JDM 5.4 but it will be over budget. Hell I even considered doing a 2JZGTE single turbo swap but the straight six is too long and tall to fit in the fox without major firwall modifications. what is the approximate price range to do the conversion on the 03-04 cobra motor to get it to work right with all gauges and accessories intact? Also thanks for your input.

 

[SlideWaySTI]

Okay I am also adding another combination but i will have to forgo gas mileage and A/C.

5. DOVE 460 with a eagle or Scat 532 stroker kit low compression with John Kazze heads then run a turbo behind it and Built C-6. But i do not see this combo being fuel effecient.

 

[2000xp8]

A 460 is just unecessary and ridiculously heavy and you need like a 4+ inch cowl hood which looks horrible.

Your #1 combo, just scratch that off the list, not a chance it will hold.

3,4 are good choices but require alot of custom work, and modular engines are crazy expensive to build up, even worse when the block is aluminum.
As someone who owns an 03 cobra engine, figure on 5k+ to get the entire setup, then another 5k to modify it, and another few grand to get turbos setup on it. Probably 15 to 20 grand by the time you are done.
Using an older cobra engine would probably be better anyway for a turbo, because to run one on an 03 cobra engine you have to remove all the 03/04 specific parts anyway.
Still, no way in hell it's all coming in under 12 grand.


The 408 would probably be easiest and the cheapest on your list.

I'd also consider a 347 R, boss or dart block setup, with a procharger D1 or vortech Ysi.
This may be the physically the easiest way to do it, with no heavily customized parts needed. Even with a turbo setup it will be good. a 302 based block setup can be done by pretty much picking your parts and installing.

Don't forget either that depending on your tuners skills anything with pushrods on the list may require a standalone system. I'd seen cars at 650rwhp on the stock computer, but not all shops are going to be willing to attempt that for you.

 

[Shaolin Crane]

427W FTW

 

[FastDriver]

A 460 is just unecessary and ridiculously heavy and you need like a 4+ inch cowl hood which looks horrible.

Concur, and Kaase's heads will not be cheap.

Your #1 combo, just scratch that off the list, not a chance it will hold.

Absolutely true.

3,4 are good choices but require alot of custom work, and modular engines are crazy expensive to build up, even worse when the block is aluminum.
As someone who owns an 03 cobra engine, figure on 5k+ to get the entire setup, then another 5k to modify it, and another few grand to get turbos setup on it. Probably 15 to 20 grand by the time you are done.
Using an older cobra engine would probably be better anyway for a turbo, because to run one on an 03 cobra engine you have to remove all the 03/04 specific parts anyway.
Still, no way in hell it's all coming in under 12 grand.

What '03 specific stuff? The blower? You know the modular stuff better than I do, but the reason I would think that the '03-'04 Cobra stuff would be better is because the internals are stronger, the heads flow more, and the pistons yield an 8.5:1 compression ratio which I believe is perfect for a boosted motor on pump gas. I'm not that familiar with the prices, but wouldn't it be cheaper to get an '03 cobra long-block (up to the heads, not including the blower) than acquiring and building a teksid? I certainly don't think it would be wise to try to push 700rwhp+ through a stock pre-'03 Cobra shortblock.

The 408 would probably be easiest and the cheapest on your list.

The 408 might be cheaper, maybe, but maybe not after the machine work and forged internals, and you've got a weaker block than the modulars. I'll try to do a little research on 351W block strength. One thing is for sure, getting in the 700+rwhp range on pump gas would be a breeze with that much displacement.

Don't forget either that depending on your tuners skills anything with pushrods on the list may require a standalone system. I'd seen cars at 650rwhp on the stock computer, but not all shops are going to be willing to attempt that for you.

Michael Bell at Dayton Performance is a competent tuner who wanted to do mine with a piggyback on the EEC IV. I didn't let him because I was set on going with a standalone, but he might be able to help you.

Chris

 

[FastDriver]

The "internet consensus" is about 800hp for the 351W blocks. However some have mentioned seeing people push over 1000hp with good internals in them. Like the 302s, the factory blocks are all 2-bolt mains and shouldn't be spun beyond around 7k rpm.

That said, I didn't see people who were actually splitting them. Maybe they're tougher than popular opinion?

Chris

 

[2000xp8]

What '03 specific stuff? The blower? You know the modular stuff better than I do, but the reason I would think that the '03-'04 Cobra stuff would be better is because the internals are stronger, the heads flow more, and the pistons yield an 8.5:1 compression ratio which I believe is perfect for a boosted motor on pump gas. I'm not that familiar with the prices, but wouldn't it be cheaper to get an '03 cobra long-block (up to the heads, not including the blower) than acquiring and building a teksid? I certainly don't think it would be wise to try to push 700rwhp+ through a stock pre-'03 Cobra shortblock.

Even trying to push 700rwhp through an 03/04 cobra long block is risky. Ya, some guys get away with it, but realistically 600rwhp is really the max, and even at that you may not have longevity on your side.
Ya, there is guys who have made 800 before it blew up, but there is also guys that have blown them up at 575rwhp.
By the way, if you splatter an 03 cobra engine, you are looking at like a $5000 rebuild.
Gaskets and bolts alone run you $500.

My thoughts are if you really want big numbers, and the engine is already out of the car, might as well build the shortblock while it's out rather than ruining something good.

Since the 03/04 cobra timing cover, accessory setup and intake is unique to it, and none of those parts work with a turbo setup, it may just be easier and cheaper to buy a $1000 older cobra engine and build it up with all high end parts.

Check svtperformances terminator parts for sale section. Guys trade parts all the time to go turbo.

As far as the 351 blocks not splitting, an engine doesn't need to split to get ruined, if it flexes under stress, i'm sure you know the damage that does to pistons, cylinders and rings.
With that said, i have no clue what a 351 based block will put up with.

 

[Trboh22]

Seems to be plenty of people on turbomustangs.cooom who are making plenty of H.P. On a well put together 351w Setup...not much in the swap to speak of, and B&G Custom turbo and others offer Hot side kits for 351's in Fox's that would be work for ya

 

[FastDriver]

2000xp8,

That's some good information and it was articulated well. I'm a little surprised to hear that the '03 Cobra engines are maxed at 600 as I wouldn't hesitate to push 500rwhp from a stock shortblocked 5.0. For that matter, given how cheap you can find them (500-800 dollars for used long-blocks are easy to find) I wouldn't hesitate to build a 600 rwhp project with one. I've seen it done several times even with stock internals. I have also seen, or at least read about, several 1000+ hp stock '03+ Cobra shortblocks.

I hear you about the 351s. It seems like most guys that try pushing that kind of power through them are using block filler to stiffen them up.

I agree with you, though. The best way to build a reliable really powerful motor is from the ground up using good parts. That's how I did it. However, that's not cheap. I'm an engineer at heart, though. I like to "over build" my equipment. I wanted my engine to make 1200 flywheel hp, so I built a 1600hp, or better, shortblock.

But, that wasn't necessary to reach the OP or my power goal. After the short research into the 351 blocks, that's the way I would go in the OP's shoes. 700rwhp+ on pump gas, check. Reliable? Depends on the parts its built with, how much power, and how its driven. Less than 12k? For the motor and turbos sure, it can be done. It does seem a little short-sighted though. He's going to need some serious drivetrain, fuel system, and suspension components to make it work. It wouldn't be hard at all to put 12k just into those things. Nevertheless, if the OP is serious this would be a good way to go. I like my little 331, though

On a side note related to under-building blocks, I know a guy who made over 1000rwhp through a Ford Sportsman block using a pair of 61mm turbos! He spent some dough on the top end and the tuning, but surprisingly little on the bottom end. His car ran 8.50s at ~160mph (maybe a bit over that) and it was the quickest actual street mustang South of Atlanta for a couple of years (that we knew of). You know as well as I do that a Ford Sportsman is not significantly stronger than a stock 5.0 HO block, and I couldn't believe when he told me that it was a ford sportsman. He under-built his shortblock, and it worked great for a while but he paid for it in the long run. He's broken 3 shortblocks at this point. I don't think he'll do it again.

Even trying to push 700rwhp through an 03/04 cobra long block is risky. Ya, some guys get away with it, but realistically 600rwhp is really the max, and even at that you may not have longevity on your side.
Ya, there is guys who have made 800 before it blew up, but there is also guys that have blown them up at 575rwhp.
By the way, if you splatter an 03 cobra engine, you are looking at like a $5000 rebuild.
Gaskets and bolts alone run you $500.

My thoughts are if you really want big numbers, and the engine is already out of the car, might as well build the shortblock while it's out rather than ruining something good.

Since the 03/04 cobra timing cover, accessory setup and intake is unique to it, and none of those parts work with a turbo setup, it may just be easier and cheaper to buy a $1000 older cobra engine and build it up with all high end parts.

Check svtperformances terminator parts for sale section. Guys trade parts all the time to go turbo.

As far as the 351 blocks not splitting, an engine doesn't need to split to get ruined, if it flexes under stress, i'm sure you know the damage that does to pistons, cylinders and rings.
With that said, i have no clue what a 351 based block will put up with.

 

[SlideWaySTI]

Very good input from everyone. After picking the brain of several tuners and engine builders. Its looking like i am going with a Boss 302R or Boss 351R block. Due to the numerous miscellanous expenses and technical things to do. I am going to spend the money, build a very strong foundation and run a single or twin turbos on it. Most of the tuners are telling me that it really is not worth it for streetability to go more than 800RWHP due to the fact that the Fox chassis has to be substantionally reinforced to be able to apply that amount of horspower on the street not to mention like you guys stated the additional money invested in the suspension too. So its more than likey going to be a built Boss block 331,347 or 408,417,427 low compression with at least AFR or TFS 205 or 225 heads with a single or twin setup. I am going to have to budget out about 15k though all said and done. By the way what power difference HP and Tq will i gain with the bigger cubes verses the 331, 347? How much of an RPM advantage are the smaller motors going to have and will this be a factor in the power band going with a turbo set-up?

 

[2000xp8]

I see no use for a 331, it's not much if any more expenisve to just build the 347.

 

[FastDriver]

Beg to differ with you on that one, 2000xp8. I built a 331, and I'd rather have my setup than a 347, though I was in your camp at one point. Talk to the big name piston companies like Diamond, CP, etc... They will probably be able to persuade you, too. The added compression height of the pistons means they can handle more stress, aka more boost. In a high-boost motor, the extra 75 thousandths in compression height is a worthwhile trade-off. In just about any other situation, I would agree with you. I would never build an n/a 331 from scratch. If I were going to keep the boost and power low, then I wouldn't mind going with the extra cubes, but I didn't build a Dart block with billet internals to keep the boost low.

The only other way I would've considered building it is with the same crank and a 4.125 bore instead of my 4.030 bore. That is another way to make a 347, or in the case of a 3.4" crank it would make a 363. The reason I elected the smaller bore is because I want to keep this combination forever, and am absolutely sure that the extra wall thickness will come in handy when it's time to rebuild, especially if I run into some engine damage along the way.

 

[FastDriver]

Very good input from everyone. After picking the brain of several tuners and engine builders. Its looking like i am going with a Boss 302R or Boss 351R block. Due to the numerous miscellanous expenses and technical things to do. I am going to spend the money, build a very strong foundation and run a single or twin turbos on it.

sounds like the right idea.

Most of the tuners are telling me that it really is not worth it for streetability to go more than 800RWHP due to the fact that the Fox chassis has to be substantionally reinforced to be able to apply that amount of horspower on the street not to mention like you guys stated the additional money invested in the suspension too.

I can tell you first hand that you will never be able to put 800 rwhp down with a manual tranny unless you are on slicks. I built my car right, and it is still scary as **** at that power level and not fun to control.... ok maybe a little .

So its more than likey going to be a built Boss block 331,347 or 408,417,427 low compression with at least AFR or TFS 205 or 225 heads with a single or twin setup.

Don't be afraid of big heads, just cam it right. I haven't seen another 331 do what mine did at 14psi. I give the credit to the combination of AFR205s, Ed Curtis' custom cam, and the TFS-R box intake.

I am going to have to budget out about 15k though all said and done.

For the engine, that is feasible. I wish I'd known what I was getting into when I started though, because I spent more than I thought I would. If you'd like to see the details, shoot me a PM and then I'll send my phone number and email and I can show you every dollar I've spent on the combo. You don't have to do it the way I did because I was not sparing any expense. It can still be done well and for significantly less than I spent.

By the way what power difference HP and Tq will i gain with the bigger cubes verses the 331, 347? How much of an RPM advantage are the smaller motors going to have and will this be a factor in the power band going with a turbo set-up?

The power that the motor can make isn't going to be limited by displacement unless you're building a race car and trying to put a mammoth turbo or two on it. I mean, if you want to make a 2000 hp 331 you could do it with the same turbo that would do it on a 408, but it would take a lot more boost to get there. The limiting factor is pump gas. If you build an 8.5:1 street car you'll be able to push 15-18 psi safely on straight pump gas (15psi is a nice conservative boost, though). The thing is 15 psi is going to be substantially more power through a 408 than it will be with a 331 or 347. My 331 put down 762rwhp at 14.5ish psi. That's basically 380-400rwhp n/a combination making double the power at 2 atmospheres of pressure. If you'd like to compare 408s, take a look at what the n/a street combos out there are making, and double that to see what would roughly be capable with a properly sized turbo. For pump gas, I think 1000rwhp on a well built 408 with an aftermarket block that wanted to rev would not be too difficult to do. I think my little 331 did damned well, and was capable of making 800rwhp to the tire and a little more if I pushed the boost and tune to the ragged edge. I'm gonna say 150ish rwhp is what you'd give up on pump gas on a similar 302 stroker vs. a 351 stroker with the same bore and similar stroke increase. You should ask yourself how much you really want to have on the street, though. I went with the 302 because it's so compact it will fit handily in any other platform should I choose to ever take it out of the mustang. Plus, I'm not even planning to keep it at the power it's capable of on pump gas, anyway. 600rwhp is plenty enough for me.

A well built 351 stroker in an aftermarket block will rev its ass off, too. They have more rotating mass in the internals, but they also have significantly bigger mains. The similarly built 302 stroker will never rev enough to compensate for the displacement difference.

Another nice advantage of extra displacement is the ability to spool a big turbo more quickly, which helps to make a street car a little more fun down low.

 

[2000xp8]

Beg to differ with you on that one, 2000xp8. I built a 331, and I'd rather have my setup than a 347, though I was in your camp at one point. Talk to the big name piston companies like Diamond, CP, etc... They will probably be able to persuade you, too. The added compression height of the pistons means they can handle more stress, aka more boost. In a high-boost motor, the extra 75 thousandths in compression height is a worthwhile trade-off. In just about any other situation, I would agree with you. I would never build an n/a 331 from scratch. If I were going to keep the boost and power low, then I wouldn't mind going with the extra cubes, but I didn't build a Dart block with billet internals to keep the boost low.

Guys crank out 1600rwhp with 347's, boost numbers far off the chart.
My buddy ran his 347 making over 1500rwhp for 2 straight seasons never having the shortblock apart.
And before that he drove it around on the street detuned to 900rwhp, but a street mishap ended the tradition of actually driving it around.
So i'll assume that 800rwhp or less is no fear for a good rotating assembly.

Not sure why CP would suggest that, but they aren't exactly known for pushrod piston setups, they've only been around since 98.

 

[FastDriver]

Really, because over on the turbo forums they were more recommended than any other company except JE which are always mentioned in the same sentence. You know, I deferred to you when it came to the Cobra motors despite the fact that guys have pushed them over 1000rwhp. You think they shouldn't be pushed passed 600... a 400rwhp (66%) difference. Then, you'd rather have guys listen to your advice about pistons than the techs at the most reputable custom piston companies because you've seen guys push them harder on the dragstrip?



My point is that guys in this sport will always push parts harder than they should be pushed. For another example, my car is on the old school Tremec TKO. That doesn't mean that I should tell people to push them as far as I have if they're starting from scratch.

I wasn't going for a combo that would last 2 seasons at a drag strip. I built a car with the maximum short-block strength possible in mind. I don't know how much power it will actually take, but in my mind the weakest components that will take the most abuse in the block are the aluminum pistons not the billet steel bryant crank, or billet oliver rods, or Dart Iron Eagle Block. Specifically, the weakest point in that whole shortblock is at the crown of the piston where a lot of guys have broken the crown between the top ringland and the dish in the piston where the material is the thinnest. This has happened with many different brands of pistons at that. Incidentally, adding compression height means there's more material here. So as a guy with a mechanical engineering mindset who does thorough research and took years to put this one together I found the best and asked their opinions. When techs at JE, Ross, Diamond, and CP, all of whom are mentioned in equal standing by guys like Brian Adams and Jose from forcedinductions.com, all tell me that the right way to do it is to stick with a 3.250 crank or go with a shorter connecting rod, I don't dismiss their opinions just because others have done it with less. Fortunately, I haven't lost any sleep wondering if I've made the wrong decision.

Everybody is welcome to their opinion, and most people already have some parts when they start putting an engine together that they have to build around. That's less than optimum, and my TKO tranny is an example of that. In the motor, I didn't start with any parts to build around, and neither will the OP. By all means confidently build your high-boost 347. My curiosity is why are these other guys pushing the stroke on these motors but leaving the bores alone? I mean usually guys that will sacrifice strength for displacement wouldn't even blink an eye at going with a large bore in a strip oriented car. Were these big bore 347s?

Chris