Hey everyone, I'm new to this forum (joined today actually) and I'm looking for a little advice.
I have an '05 4.7L QC and it's got about 125k miles on it. Everything runs fine, just the normal complaints of it being anemic to say the least.

I've been searching around and considering a Hemi Swap or buying a truck with a Hemi, but figured it's paid for so why bother?

So I looked at AirRam and saw their CNC machined heads and '08 intakes etc. but they're pretty expensive too once you figure in gaskets, TB adapters etc.

Then I learned just the other day the '08 4.7L (Corsair) came standard with nearly 75 more HP than the 99-07... and I have found them in wrecked Rams online for $1600.

That being said, it's cheaper, and my gains would be about the same if not more and this is power I would be STARTING with. I could always build from there with headers, SCT, Efan, new Tq Converter etc.

I know they both run off of 32 tooth tone rings, so with a new tune to meet the parameters of an '08 PCM, could this possibly be a direct bolt in?
Any input helps.

 

I don't see why not... but the Cam grind may have changed... and there may be some other changes to the heads that your PCM may not be able to control/compensate for...

But I don't see why you wouldn't see some kind of gain... I don't think it will be on the order of 75 HP, but it will be better for sure.

If I was you I'd just buy one of those junkyard motors and build it up with some better pistons, rods, maybe go .020" over and then work the heads with a nice cam and port-polish.... that might be well worth the time and $.

 

They're twin plug heads, you'd have to work around that (making both fire correctly) and get an adapter for the newer intake manifold, but I don't see why a little work won't do the trick. Bggets hurdle here will be your stock PCM (and its capabilities or lack thereof).

 

I thought that the twin plugs still operated off of a single coil on plug setup, just using more or less a jumper wire to fire on the exhaust stroke for emissions more so than performance?
Am I wrong? My other big concern was what if I came across a flex fuel model? Wonder what issues there would be with that?

 

They do.... I doubt you will have a problem getting it to work right.

Flex fuel engines are usually mechanically the same but they have bigger injectors and can accommodate for the additional demand for fuel that is created when E85 is used instead of gasoline.

You should be able to get the twin head plugs to work correctly, but you might need to upgrade your coils, as the twin fire's may output more to accommodate for the second plug.

Overall I don't see it being a "huge" workaround so it's doable, really just comes down to how much $ you want to spend and how much patience you have.

Keep in mind that you aren't going to see a 75hp increase.... there is a lot that comes into play for that difference in power. I think you might be looking at a 25-35hp increase which is respectable. You might see a bigger gain if you build an identical motor that you already have.

There are a lot of build parts for the 4.7L Engine and I bet you would be much happier with a beefed up 4.7 than having to deal with an OEM problem-box..... Just my $.02 there.

 

Thanks for the input. I guess my original thoughts were that I was hoping for the same power as the '08 with as little to no true modifications from an OEM platform as possible aside from tuning. But there seems to be the thought that whatever gains I would make, would be pretty insignificant versus rebuilding a complete "drop in" using the 99-07 platform and building/ tuning it.

I considered this; using AirRam's high compression (10:1 I beleive) domed pistons, new rods, race prepped heads, '08 intake, larger TB, CAI, headers and a new damper/ UD pullies along with a tune to build it. And I would have loved some HO cams... but I can't find them. This build, per Nick at AirRam would in theory produce about 325 RWHP... significantly more than the '08 4.7 and even the Hemi... right on line with the current Hemi's figures. Pretty impressive

Then, thinking back to when I used to build mustangs, a lot of times, when you build for more performance, a lot of times you sacrifice daily drivability & reliability... so the thought of this build kind of scared me since my truck IS my daily driver. And I don't race it, but I truly do want 300+ HP/ TQ as a truck this size should have... not only for driving but for towing, passing etc.... so this is why I considered the 310 HP '08 "Corsair" 4.7L as a direct replacement... but that doesn't sound like what I would end up getting.

Thoughts?

 

well at 10:1 compression you better believe you'll be running 91-93 octane to get those numbers... that will be an expensive daily driver..

I'd bore over .020" maybe raise the compression just a hair over stock, and build the heads... and tune for 89-91 octane..... just my thought though.

 

There's a guy on DT who put an Eaton off of a Mustang on his 4.7. Apparently first tets drive running rich and not quite tuned right and its still a beast.

 

Having to run 91-93 octane wouldn't be that much of a concern since it's only about $.20 more per gallon, or maybe $5 a tank difference, if I can get that much more power.

Plus with more power, in theory I should get better in town MPG anyhow since it wouldn't have to work as hard to get up to speed. I already have the 3.92 rearend setup which would probably make it a beast with the extra torque and ponies...
I'm thinking you may be right on rebuilding the pre '08 4.7L to be what I want.

My only concern is the reliability of a higher performance engine in a daily driver.

I wouldn't abuse it, I pamper the one I have and keep everything in good maintenance as it is, using all synthetic and turning my own wrenches... as I've gotten older, I've realized if it breaks... I have to fix it, no one else will pay to do it. So I try not to let it break.

You seem pretty experienced on the forum, how do you feel about the reliability?

 

I haven't seen or heard one in motion, but I did see the mock up of the Eaton on AirRam's website...

I actually used to drive one of the '03 terminator cobras with the Eaton on it, and granted... it's lighter and uses a 32v 4.6, IT WAS NASTY!! from the factory... so I could only imagine how it would be on the 4.7... yes it has fewer HP, but since it's only 16V the torque figures would be much better, which is what makes our heavy *** Rams move anyhow.

Curious if they had to use the adapter plates from AirRam, and what they did with the blower snout alignment? Do you have pics or a link?