2003 5.7 1500 4x upgrades

[mopar44134]

So I picked up this Ram not long ago and of course it has the tick. Runs good, crappy mileage though, 13mpg. 145k. My dakota 4.7 with 3.92's gets 17. This has 3.55s. I am currently using the truck as a daily driver back and forth to work, with plans to pull a car trailer and my 68 Barracuda to the track. I had a 2002 with the 4.7 and 3.55s, it pulled it ok, had to down shift on that hill on 71 by Lodi in ohio going to dragway 42.

BTW and it has nothing to do with this post, just bragging, if you want to see a picture of the Dakota, its on the ad for dragway 42's hang over race this year. Made the semi finals!

Back to the point, I plan on changing the cam and lifters. I've read here the valve springs maybe a concern, but i figure with the head off change those to match the cam.

I've been searching threads and have a few questions i'm hoping someone will answer.

Will I be able to tune the pcm? I've read hear about swapping to a 2005 pcm, with wiring harness swap. Is this a plug in mod or will wires have to be traced/spliced.

Which Cam? I heard mixed review about a 6.4 cam swap. Seems to me this is more geared to chargers/challengers, Hp rather than torque.

Which Lifters? 6.4's

Any head porting tips to help add torque?

While im that far in, what else should i do?

This is a non-mds truck, right?

I also read about pulling/cutting a yellow wire for the tcm. I'm not very clear on what that does. As it stands right now, this truck seams very docile off the line unless your foots in it.

Thanks in advance!

 

[HemiLonestar]

I see a significant amount of internet reading but not a significant amount of reconciliation of information. Please see answers in bold below

Will I be able to tune the pcm? - minimally but not very well or extensively; a 260 or a custom cam geared to your truck will work. Ironically, the 6.1 cam was proven to work years ago.

I've read hear about swapping to a 2005 pcm, with wiring harness swap. Is this a plug in mod or will wires have to be traced/spliced. - I cannot stress how much this is not a plug and play operation lol, however it will allow significantly greater tunability.

Which Cam? I heard mixed review about a 6.4 cam swap. Seems to me this is more geared to chargers/challengers, Hp rather than torque. - you are mixing up engine families. The 6.4 is a VVT engine; this cam will bolt into an eagle 5.7, which you do not have. 2003-2008 is pre-eagle, 2009+ 5.7 is eagle, 2011+ 6.4/392 in cars is apache. So it is a non-starter. As for cam selection beyond that, see above (unless you plan to do the PCM swap).

Which Lifters? 6.4's - all hemi lifters from 2003 to present day are forwards and backwards compatible, just boils down to whether MDS or not and that's only cylinders 1, 4, 6 & 7 in MDS applications. Luckily, not an issue for you. Simply need the latest part number non-MDS lifters. Be wary of vendors who advertise "Hellcat lifters" like they're **** stronger or some ****; it's just an excuse to try and charge more. So called Hellcat lifters are simply the latest version of the non-MDS lifter, pure and simple. Shop around.

Any head porting tips to help add torque? - porting never hurts, but most pros who make a living on these engines and have been doing it for years a don't like to give up their secrets. You can big valve these heads but whether you can really take advantage of them or not depends on whether you take the PCM plunge. Same for swapping to better heads.

While im that far in, what else should i do? - make sure the valvetrain is up to the task, specifics will depend on other decisions you make. Back in the day, two almost automatic upgrades with a cam swap was using an OEM 6.1 timing chain and tensioner and OEM 6.1 oil pump. Also back in the day, a cam swap also would include 16 6.1 OEM exhaust springs (same height as the 5.7 springs, fairly cheap and plenty strong) and 16 OEM 6.1 intake and exhaust pushrods, reason being the aftermarket cams use the 6.1 cam base circle which is different than the pre-eagle 5.7 base circle.

This is a non-mds truck, right? - Yes

I also read about pulling/cutting a yellow wire for the tcm. I'm not very clear on what that does. As it stands right now, this truck seams very docile off the line unless your foots in it. - Torque Management Reduction (TMR) mod. Pulling that wire removes the TM signal from the TCM to the PCM; the engine will not cut power at all on full throttle downshifts. Upside: makes the shift more exciting. Downside: because it doesn't pull power, when you're in say 5th gear and you mash it, it drops to 2 prime (not regular 2nd gear). Unfortunately 2P uses the same clutch set as 4th and 5th (the OD gears) which are the physically weakest ones in the case. I'd leave that one alone, especially if you plan to cam it and not change the computer because even stock it will reduce the life of your trans. Even with TM functioning the RFE is a **** trans; I'm on my third and quite likely about to go for #5 unless I say fuckit and decide to do the ZF swap now (if the $$ is there).
Thanks in advance!

 

[mopar44134]

Thanks Hemilonestar!

Transmission has been another concern of mine.

A while back i picked up a 2003 Durango 4x4, wrecked but running. 4.7 with the 45rfe. Between my Dakota and my daughter 2002 grand cherokee 4.7 4x4, spare parts if something went bad. $500 including towing the Durango to my house. A deal presented itself, sounded like a good deal at the time. So far, havent had to use it. At the time I didn't have this Ram.

Looking around i dont see a difference from 3.7 4.7 to 5.7 equipped vehicles with that trans. Is that right? Would the 45rfe from the Durango bolt right in, no other mods, to my Ram?

Thanks again!

 

[HemiLonestar]

Yep. Any vehicle listed to have a 45RFE or 545RFE will bolt right in, same trans. Computer decides how many gears you're gonna have. Only real difference is 2wd and 4wd and that's just an adapter and tailshaft swap away. If I'm not mistaken any RFE trans in a 1500 up through like 2012 should work, though I think there was a connector change going into the 4th gen (don't quote me on that). Just keep in mind not all 3.7's came with the RFE, later on they got the 42RLE. You can't use and even if you could you wouldn't want to.

 

[mopar44134]

Thanks Again! Helps when deciding what has to go in the garage lol