Unless the head is in really bad shape, or the machinist is expensive, a basic P&P is all that is needed. We're not talking a full race prep for those numbers. Getting rid of the log intake and exhaust goes a long way towards the goal. Add a good 4v carb(at least 390cfm) to replace the stock 1v to feed it. A decent cam(like a Comp 252) and timing gears to index straight up and your mostly there. Roughly 200hp @ 4k and 300tq @ 2k. No turbo needed. Very reliable.

Take the carb to around 600cfm and you start seeing hp around 300 and torque approaching 400. But you'll start having reliability issues when pushing things this far. Not a suprise when your around twice what you started with.

But...if your not planning internal engine changes then a turbo will be needed to force more air through. And that can be a big headache to get working correctly.

Or if your really wanting to push the power envelope then by all means go forced induction. But be prepared for parts to break.

 

You will have a hard time making a real world 2oohp at the rear wheels without spending a substanstial amount of money and the power is going to be higher in the rpm band than you want it to be. Forced induction isn't perfect, but it can work really good with some time and effort. As far as 300hp and 400lb of torque NA, its just not going to happen in a daily driver that has to pull a trailer.

 

Never said those would be rear wheel numbers. Expect at least 25% paracitic loss.

Whether NA or FI, a 300hp BB6 won't be reliable if it needs to pull a loaded trailer daily. For that I'll stick with my "other" inline 6. (Cummins ISB)

If it is just a daily driver, then the NA 300hp/400tq will work quite well. At least I haven't heard any complaints from Col Flashman on that subject.

 

Got to disagree with you on that, the 300 is more than reliable pulling a trailer. Mine spent 95 pecent of its life being hooked to something as it is a farm truck. We have pulled anything and everything with it from a thousand pound trailer to 18 thousand pounds of water and we never have had any problems with it and we have 262k miles on it. You just have to take care of it and use it withing the confines that it was desinged and it will do everything you ever wanted it to do.

 

Jon, please re-read what I said, your taking one small part of my statement out of context.

I'll restate it. Any engine that is modified to produce twice, or more, the power is was designed for will have reliability issues if put under a heavy load on a daily basis. In the case of a 300cid/4.9l I6, whether it is naturally aspirated or force injected, that is modified to produce 300hp/400tq will have issues if expected to pull heavy loads on a daily basis.

Conversely, a properly maintained stock 300/4.9 will be able handle the same kind of abuse for a segificantly longer time.

You'll note from my signature that I have a high mileage 300. It has been for years as a daily driver and heavy pack mule at need. considering that it has exactly the wrong differential for heavy pulling I've been amazed at what it will actually do and ask for more. I have no illusions that it would still be running, without major overhaul, had modified to the afor mentioned power levels and still used it the same way. The cost of additional power production is accelerated ware.

Or are you saying that you have an engine that is producing twice it's stock output, used and abused in the manor that any good farm truck should be (including regular maintenance) and have had no reliability issues?

 

Mine has been worked over some, not to produce twice as much power though. It has a cam, headers, headwork, computer programing, a custom ram air intake, and ignition system, and some other mods that arn't really performance mods. It has had these mods sence it was two years old, my uncle liked to work on trucks and did all this work when it lost a head gasket.
I didn't mean to distort what you were saying. I just wanted to make sure everyone was aware that a 300 wouldn't have problems handling towing duties.

I would estimate that with a well thought out turbo build should last for at least 125k miles as long as it is taken care of. This is much longer than anyone will hold on to it in all probablility and it wouldn't take much to freshen it up again and run another 125 if you so desired.

 

Hold on to a truck for 125k miles? Have you read many of the posts in here? Most of us have had our trucks for at least that long with no intentions of selling. Many of us, myself included, have put more than twice that number of miles on their trucks and have no intention of selling.

If I was going to build a 300 that made 225 hp and 400 ft-lbs I would go with a turbo, but I'd pick one that was a little bit closer to what I needed. I'd choose one from an application closer to the displacement and rpm range as the engine I was building. Maybe from a late 70's turbo Trans Am or a mid 80's 3.8 turbo. I also would not do a draw through setup. That's a good recipe for a large explosion at the worst and a fuel distribution problem at the best. A blow through setup fixes both of those problems as well as allows an intercooler to be used. You don't need a special carb to run low boost like we're talking about. The single best reason to go for a turbo is because 400 ft-lbs at any rpm is at the very limit of the 300's capability. Thermodynamically you just can't get any more out of it.

On the other hand, you can build a NA 300 that will almost get to the torque number you are looking for, while easily achieving that power level. If a store bought 300 that makes 300 hp at 4000 rpm and 400 ft-lbs at 3200 can be had for $4500, imagine what you could do in your back yard for a lot less.

I also think there is a little too much emphasis being place on the torque peak being under 2000 rpm. That is a waste of so much potential. A stock EFI 300 makes peak torque at around 2200 rpm, but is within 1% of that number down to 1500 rpm and probably lower. Mine makes 270 ft-lbs +/-1 ft-lb at the wheels from 1500 rpm until around 3000 rpm. I could add a lot of airflow to it without compromising the low end torque. A ported head and mild cam would probably move the peak up to around 290 ft-lbs at 2500-2700 rpm, but at 1500 I would still have at least as much as before, plus I would have 600-800 more usable rpm on top.

Any book or magazine you pick up will tell you how important it is to build for torque and that you should give up a little top end for the sake of low end. I would never say this about most engines, but with the 300 it is well worth giving up 10 ft-lbs on the bottom to gain 10 hp on the top. A 225 hp/400 ft-lb engine sounds neat, but it would suck to drive around compared to a more well rounded combination. That engine would be a lot more fun and useful with 360 ft-lbs and 250 hp.

 

You make some good points. What I was saying was that if a guy did build an engine today, he probable wont keep the truck for another 125k and if he does, he wont be out any money to rebuild it again. At that point you are looking at an engine that if it was rebuilt at 200k and again at 325k would last untill 450k if the engine needed to be rebuilt every 125k which it probably wont, it will probably run longer than that. The draw through carb is WAY easier to design and install over a blow through setup. The only down side is that you cant run an intercooler because fuel pudeling in the intercooler could cause an explosion. If you run a blow through setup, you must use a carb that is designed for it, otherwise it probable wont run at all or if it does, it will run very crappy. The fuel pressure would also have to be increased by whatever the boost amount is because the foat bowl will now be pressurised. If you jump over to www.fordsix.com and look in the turbo section, you will get a good idea of what some of the fastest guys in the world of inline 6's run for a setup and there is a wealth of turbo knowledge there

As I said earlier about the turbo from the dodge, it will work pretty good as the 94-98's had a smaller turbo, a H35, that will work quite well in this application. You can run a garrett T04B with a 62 trim also, as it is a quite popular choice for this set up.
I guess the morale of the story is get online and read all you can and make the desion yourself.

The idea about the trans am turbo sounds like a good idea, but I dont know much about them so its hard to say. If you have a junkyard near you it might be a good idea to cruise through it and see whats there and them go home and look up the turbo maps and see which ones will fit in your application

 

honestly, if your gonna turbo it, why waste the time money building a carbed set up? your obviously gonna want to upgrade the intake to a 4 bbl, then get a 4bbl carb, by the time thats all said and done your gonna be lookin at 500+ (this is assumuming you get a new manifold and a used carb) by the time you have spent all that, you would have been MUCH better off going to the junk yard/hunting around on this forum (someone will probly give you one) and get an intake off a fuelie motor, (and the head) and go buy a megasquirt stand alone injection system, cause you can EASILY custom tune it to your individual needs, and all it is is the PCM, software (for your PC) then you program the PCM to accept whatever components you choose to use, (based off what you need for injector sizes, what you have laying around(cheap/free, lol) etc) you can use parts off any vehicle, get there operating voltages, punch them into the program on your PC, the the PCM stores them to control your custom fuel injection sytem. to see a bunch of videos regarding this, just go to www.youtube.com
and search under "Megasquirt" or "Megasquirt fuel injection" i ASSURE you you will be MUCH happier with the results, and so will your 300. honestly a carburater is a waste of time, at least when turbo charging. another option for you if you realy want to stay carburated would be a GMC 4-71 blower, there CHEAP, perfectly sized for a smaller cubic inch application, and still plentiful, there factory application was on 4 cylinder 71 series DETROIT two-stroke diesels, but can be and have been clearenced for gasoline applications (diesels as you know don't have fuel running through the intake system) the hardest part here is the intake/blower drive, but i have seen it done.

get INLINE!

 

OK.
The build a 390cfm 4bbl
HX 35 turbo (copper head gasket)& wastegated to about 8psi
Headwork (port/ polish) maybe mill it
Comp 252 cam
2.25" exaust out
Chevy rockers
A 40,000 volt coil
a 390 V8 Radiator and a 1500cfm E-fan to keep things cool
245/70 R 19.5 Load H tires
4.56 gears
a Gear vendor OD unit
Is this a pulling combo???
What else did I miss?

 

I know that I'm beating a dead horse here, but...

Unless your planning to rev this engine into the 6000+ rpm range stay away from the diesel turbo's. The smaller engines get away with using them because of the rpm range they are targeting (2.3l's in the 8k+). And the 5L V8's because they are reving over 6k. This makes some sense because they are trying for similiar air volumes in these ranges to what the diesels are pushing sub 2500rpm.

It's really simple math. If a 5.9l with 17:1 compression pushs enough air to generate 8psi of boost at 1500rpm, a 4.9l with 8:1 is going to have to rev segnificantly higher to generate the same boost level.

I'm trying to discourage you from going turbo, but unless your planning a high reving engine the diesel turbo's will be a massive disappointment for you.


For a turbo application the 2.25" exhaust is going to be a serious issue, that's the stock diameter. you'll need at least 3" to reduce drive pressures to a managable level.

Don't forget to use head studs with a boost application.

At 8psi you shouldn't need a cooper gasket. They also have a big headache attached, the tendency to leak coolant. Stick with a Felpro p/n 1024. This is the same one that is used by The Frenchtown Flyer. It will hold N/A and mild boosted heads just fine. And should be around $40 compared to $150+ for a cooper one, if you can find one.

Best advice for turbo selection: Go to sights like TurboMustangs and read thier advice on selecting junkyard turbo's. Barring that, look at OEM turbo applications with similiar displacements as donors.

 

If you want to go turbo, go to fordsix.com, there is a wealth of information there about different combinations and the results people are having.

 

I would think twice before you mill the head on a turbo engine. Milling the head does two things that might be undesirable on a turbo engine. Obviously it raises the compression ration, but it also thins the deck surface and might compromise its ability to keep the head gasket clamped down.

Raising the compression on an engine is usally a good thing, but before you do it on an artificially aspirated engine you need to decide if you want the engine to work best with the boost on or not. If you want good throttle response and mileage when you are not under boost raising the compression is the thing to do. If you want max power when under boost you want the compression as low as practical to prevent detonation and increase volumetric efficiency.

 

minus the turbo then.
IS the rest of the build good for power in the 1-3k range
OK my goal has changed to a NA 300 with 200hp and about 330ftlbs not reving ANY more than 3500rpm

 

Add Cloyes adjustable timing gears (3 indexed keyways 4* retard/straitup/4* advance) so that you can 0 index the cam.

2 1/2" pipes.

EFI exhaust manafolds(a little cleanup with a dye grinder and they are nearly as good as shorty headers). Unless you really want long tube headers.

Hypereutetic(sp?) pistons.

Maybe replace the mechanical fuel pump with an electric performance one and a pressure regulator with return line (helps keep the electric pump cool).