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4.7 low end build?

3K views 14 replies 4 participants last post by  Lear96 
#1 ·
Forgive me if I'm beating the dead horse here, I've been researching threads and such for the prospect of adding some low end grunt to a 4.7L. Most everything I'm finding is from '08 and earlier, and folks are saying there's not much else besides gears and a custom PCM program for the motor, has anything changes in recent years? What can be done for low end with these motors?
 
#2 ·
There is a lot out there for the 4.7 depending on what year you have. SCT and other companies make programmers for your truck and yes they do seem to add about a 3-5% horsepower and torque increase depending on mods. That translates to about 10hp and 10ft-tq . That translates to about $40 per horsepower so I feel like that pretty good. You can do a E-Fan conversion and that help free up a little horse power and throttle response, HO manifold conversion depending on the year, short tube headers (JBA makes a good set), Exhaust, Intake, HO cams (depending on year) and so on.
 
#3 ·
What I'm looking at doing is basically building my own '08+ motor. Buying the whole '08 top end and having my motor shop build the block as an '08, and then either buying an '08 computer or reprogramming mine. From my research this seems to be my most cost effective plan since my motor is in need of a rebuild anyway. Cylinder #7 dropped the valve seat and caused some pretty significant piston damage and it damaged the valve bed beyond repair...remarkably the crosshashing from the factory is still there after 273,000 miles!
 
#6 ·
you could do an 08 engine swap. Would be cool on an older gen 4.7 and I havent seen one done yet. But if you have the pockets to do it go for it. If not then an easier route and more readily available parts would be to swap in a hemi. Wiring is a pain, but the power you could make would be better. but then we are talking beefing the trans up. It all depends on what route you go
 
#7 ·
Kicked around the idea of a hemi swap, but unfortunately for a poor college student a hemi swap just isn't in the realm of possibilities. I like the hemi motors, but not to the tune of $5,000...In researching this arrangement I'm only going to be set back about $3,000-$3,500, and that is much much more reasonable. Plus I just like the idea of being able to say "Yeah, nothing about that truck came from the factory that way."
 
#9 ·
yes but the aftermarket sucks for the 4.7, thats why i am doing a 426 swap. Any how, a hemi would be much easier and take much of the guessing and calculations out of the low end build. But if you so feel to do so, by all means. Id like to see it done. Ive been in your shoes. I encourage that kind of stuff
 
#8 ·
I think a Hemi swap would be just about as easy. Going from a 8 spark plug JTEC motor to a 16 spark plug NGC motor is going to be a pain. Also for the cost I would think that you could build your motor. Maybe get a set of HO cams and get them ground to 206s or something like that with a 08 manifold. Should really wake the old girl up. IMOP any way take it for what it is.
 
#10 ·
I have to agree with that statement. But there is some aftermarket out there depending on what your goals are. And that's the key. Wheat are you goals? I would say any thing over 275rwhp naturally aspirated is going to be about the limit on a 4.7 unless you plan on paying crazy money. But if your goals are sub 250rwhp/330tq then I would say its easily achievable. If your goal is over 350whp then the hemi is going to be the way to go with out a question.
 
#11 ·
^ nicely said.

OP, rebuilt engine, 08+intake, bigger bored and polished throttle body, clutch fan delete and add an e-fan, intake, headers, exhaust, and if you could find some HO cams, you are looking at a nice build.

I have a intake, bigger throttle body, fan delete, colder thermostat with colder plugs, headers, retuned computer and run 89 octance, e-fan, deleted 3rd cat, 3 inch straight pipe exhaust and some other things im most likely forgetting. buddy of mine has the similar setup on a 4x4 with massive 35s, and dynoed at IIRC 240 to the wheels. So I would be about the same if not more because of the less rotational interia and drivetrain loss.
 
#12 · (Edited)
And you can always take it a steep beyond that.

.010-.040 bore
8.5 to 12.0 compression pistons
206 to 218 cams (224s may be out there)
After market valves, valve springs, light head porting, etc
And so on.

You also have the option of
ARP Head Studs
Solid lifter/tensioner conversion
HO parts (pistons, larger exhaust valves, etc)

I am sure there are other parts that I am forgetting about. A lot depends on your application and if you are a 2WD or 4x4. In a race only motor 12:1 compression and a 218 cam with solid lifter/tensioners would probably make 300 horses. Of course that would not be a very street friendly set up for a truck but who knows.
 
#13 ·
Now you are talking going in depth with the tuning. SCT is the only one that you can have custom tunes made, or the truck can have the PCM tuned. But the motor has to be finished and said and done before that happens, then its finding the person who can do that
 
#15 ·
My goal is a modest 250-260 rwhp. I don't need 300 rwhp out of a truck, I'm looking for torque out of my build. Also this girl is going to be my DD so I don't want to be paying gas for 300 rwhp anyway haha.

At the end of the day, I want it to tow a hefty amount without having a torque band of 4,000 RPM...
 
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