Building a 5.2

[Epinder92]

Okay so I own a 1997 ram 1500 5.2. my mechanic gave my the truck back with little oil creating a knock. My buddy told me you can swap the heads and a cam and get 400 hp out the 5.2 magnum. So my question is. Can I run a stock computer and intake and fuel system with a certain head and can setup. What do I need to be able to support a head and cam swap. From roller rockers, ecu flashing, I want to know start to finish what I need to successfully build a daily drivable 400 ish hp truck. I’d say I’m willing to spend about 3-5k on this project just for the engine. In more research I’ve read I’ll need to upgrade the 1500 5 speed into a nv4500 to handle the power ect. But that’s whole other situation. Right now I just really want almost like a proper build sheet to start with so I know what to buy and what I need to make this a solid motor. Thanks I’m advance

 

[Riccochet]

You're in the wrong sub forum.

But, to answer your question, you're going to need a lot more work than just heads and cam on a N/A 318 Magnum to get 400 RWHP. At the very least you are looking at forged pistons, forged rods, cam, heads, headers, full exhaust, programmable ignition system, machine shop work to deck the block, line bore, all new cam bearings. That 9.1:1 compression ratio will need to go up a bit....a lot. While having the block apart it's probably a good idea to get a forged crank, new crank bearings.

You can gain a little power with better flowing heads and a more aggressive cam, but not 400 RWHP kind of gains. The older LA 318's took power a lot better than the Magnum's, that's for sure.

More than half of your budget would be heads alone to support that kind of power.

 

[Epinder92]

So I mean I don’t need nessesarily 400 whp. If the motor makes a little less then 400 and I can get atleast 300-350 to the wheels I think I’ll be happy. I’m already somewhat happy with the torque these little v8s produce stock. I’d just love to have more. Have you built on or do you have recommendations for a mild sweet build

 

[Riccochet]

No, not really. The magnum's are money pits. They can produce the power, but you're going to spend money to get it. To get power out of them is a culmination of parts and tuning. A couple grand might get you another 20-40 HP. If it were me, I'd find an LA 360 and swap it. Now you have a motor than can take mods that will mean something.

 

[Wild one]

So I mean I don’t need nessesarily 400 whp. If the motor makes a little less then 400 and I can get atleast 300-350 to the wheels I think I’ll be happy. I’m already somewhat happy with the torque these little v8s produce stock. I’d just love to have more. Have you built on or do you have recommendations for a mild sweet build

Get ahold of these guys,and talk to them about what you want to do,and the kind of budget you have.

Hughes Engines

 

[crazykid1994]

Hughes engines for sure. You’re better off swapping to the 360 block though. It’ll be better and more reliable power due to the larger displacement already. Or a hemi swap. Either way a standalone computer system may do you better than trying to use the old obd2 computer. It will give you better control of fuel injection and timing. I would contact frp tuning to see what he can do for you. He was big in the 2nd gen trucks.

 

[Yeret]

The factory Magnum heads will support 400 horsepower, but that's pretty much the ceiling.

Factory "kegger" is fantastic for low-end torque, but falls off quickly even at mid RPM. It flows about 180 CFM per runner, the factory heads are around 210...

Factory cam supports more flow than you'd think. I think it's about .410" net lift on the intake side, which is about where the head stops flowing.
Compression is okay on paper, but said number seems dependent on a "zero" deck block, which never happens in practice. Magnum engines seem to have a rather large piston-to-deck clearance, which robs compression and therefore power. Thin (.027") head gaskets can be a cheap way to regain some of this, but the only way to really get all of the designed compression back is to have the cylinder decks "zeroed."

Factory pistons add about +11.23cc to chamber volume and are cast, meaning they have limited reliability at high RPMs or with forced induction. Most forged offerings add only around 5cc. This will raise the compression substantially, especially with the factory cam. You can swap the factory cam to ease the dynamic ratio, but now the heads are going to be a bottleneck...

Also, don't even think for a moment that the factory tuning is going to support any real mods. Hell, a lot of second-gen trucks are running around with the "death flash," which does nothing but rob you of even the factory-designed horsepower. Fortunately, there are guys around who do still do tuning (Flyin' Ryan, for example).

Can a Magnum 318 make 400 horsepower? I have no doubt. Are you going to make it on the cheap? No.

Oh, and the factory fuel injectors won't handle 400 horsepower. It's arguable if the fuel pump could either.

 

[Anthonystempak]

The weak link is the factory magnum heads, they crack and won't seal so they leak oil bad.
I believe these rt hemi heads are junkyard units around 500$ the magnum roller motor is a good motor. I'd have the rotating assembly lightened and balanced at least balanced, if you not gonna get factory forged parts.

I would either bump up the compression to 10.5 to 1 or at least deck the heads, long tube headers, Edelbrock airgap rpm intake with the efi as well. I would look for a comp cams 540" lift or so and chip to go with the cam and headers. Fuel these days is a huge problem getting gas that will even run let alone the rocket premium sometimes coming outa the pumps. Ask for a 95 octane premium tune and use some premium and octane booster

 

[Anthonystempak]

Don't forget to do some cleanup porting and polishing

https://www.motortrend.com/how-to/mopp-0407-magnum-rt-cylinder-heads/amp/

 

[Anthonystempak]

The 6.4 forged crank drops right into the 318 l believe

 

[Anthonystempak]

I bought a set of ebay sprinter stainless steel headers for my 4.0 jeep and besides the welding being off (but worked) for that wierd flange setup they are a nice set of non rusting +10hp headers m https://www.ebay.com/itm/2351698236...wgbhJfWD0aquUehxcPsnFzOHCpvT|tkp:BFBMovn9oNBi

 

[Anthonystempak]

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[Anthonystempak]

Another thing to do is swap the 1st of the mds 5.7 hemis will bolt straight in. You get better heads and what 400hp to start depending on which motor you get. https://www.performanceinjectionequipment.com/gen-3-hemi-heads again head decking and porting and headers and cam and chip and k&N

 

[Anthonystempak]

https://www.onallcylinders.com/2021...de-bore-stroke-cylinder-heads-cam-specs-more/ atleast 350hp to start. Porting and compression a chip,cam,headers will be atleast 75hp with (any timing and GAS

 

[Anthonystempak]

Those gen lll hemis are like 500$ bucks for everything in Texas although there set to run in 100+ temps

 

[Anthonystempak]

I would do a gen lll 5.7 with mds and get a set of ported decked factory apache heads that come on the genlll

 

[Anthonystempak]

The mds motors can get up to 30+ mpg if you can drive in eco mode. Once your on the gas it's a regular motor

 

[Anthonystempak]

It's probably hard to see. But it's 36mpg from a etorque 5.7
hemi I'm putting in my gen2 trx

 

[Anthonystempak]

I would kinda like to adapt the jeeps 4xe electrick to gas option with a hurricane or pentastar as a xtracab1500 4x4 donor vehicle

 

[G-Ride990]

Holy self-reply posts batman!

I am calling BS on this. No way in hell you are getting 30+ mpg with a hemi in a RAM period.

There are plenty of guys here claiming better fuel economy disabling MDS completely too. MDS is ****!