73 dart hemi swap help

[73dartswing]

So I'm extremely new to mopar. Just bought my first mopar 2 weeks ago and I want to do a hemi swap on it. I've done lsx swaps into old chevy's and all that just never really dabbled much into mopar because I've always seen Chevy as cheaper and easier because that's what I grew up on. I just need some basic information on the swap from someone that has done it.

First, will I need to swap the k member from an origional slant 6 dart?
Will a 5.7 hemi out of a truck fit under the stock hood or should I go with a motor out of a magnum or charger?
Will the stock 904 transmission and rear end hold up to the power as long as I don't stomp on it?
Will there be any major clearance issues? (Fender wells, power steering, heater etc)


I know this is a big task for someone new to mopar and I don't mean to sound snotty but I don't need a bunch of people telling me that.

The reason I'm doing this swap is because I'm going to be driving from San Diego to Chicago in 7 months and I feel like the stock slant 6 Will have a ton of trouble making it over the mountains. And I don't want any problems. Also its a decent start to the future of the car

 

[thesiren74]

I wouled eventually like to do this same swap in my duster,congrats on your new mopar! There's a lot of information on this site and people to help you.

 

[joeboy]

here is info I sent via PM to a member, should be a start...

As far as a Hemi swap goes, it really comes down to a few decisions about your budget and expectation/desires before you can really have a "plan". There are many pieces of the puzzle that are personal preference just like any build. That being said here is what I think.

1st major question: what you want to do about your front suspension, factory K member or aftermarket K.

The factory K is doable ( v8 ), but really tight at the torsion bars, manual steering-box, and passenger fender. REALLY TIGHT, but I've run it with no issues for now.

TTI exhaust sells headers for the swap, as well as motor mounts, and an oil-filter relocate/delete plate necessary to run their mounts in an a-body. As far as other exhaust options I believe the HEMI car manifolds will fit wit the factory K, but require minor passenger frame mods. The SRT manifolds fit with the aftermarket K's

The benefit of the aftermarket K in my book is updated suspension with rack/pinion, engine clearance on all sides, and the decreased need for retaining the torsion bar crossmember that seems to be in the way for almost all OD trans.

Question 2: Which motor?

The most plentiful engine is the 03-08 5.7, two variations, truck and car. Truck is easier to install due to accesories, and car is prettier due to intake design and cover. The truck intake fits under the hood fine, the car engine has alternator to frame rail interference that can be fixed with minor trimming.

6.1 is more rare, and comes with a higher price tag. easily double.

the newer 09+ 5.7 and 6.4 have better flowing heads (but the older hemi heads still flow massive #'s), variable runner intakes, and VVT that are all really good tech, but create more problems with aftermarket ECUs. the newer do make more power with the headaches involved...

Question 3: EFI vs Carb, I personally dont see the benefit of pulling a carbed motor for another of the same, but that just me... if carb you still would need to get a computer/controller for the coil packs, buy a intake and find a carb... so in my book the saving really comes from not building a fuel system for the EFI, which isn't that great to run a carb on a motor that wasn.t designed too.

EFI: so many options... anywhere from $1500ish to $3000

simplest EFI system is a factory 05 RAM ECU reprogrammed and a "standalone harness" for the engine, hook up like 5 wires, fuel pump/system and elec fan and it should run. Most guys get this stuf through "hotwire auto". for this set-up you need a DBW throttle pedal avail from street & performance or bouchillon performance or mopar factory part.

other EFI systems include FAST XFI, EFI source Hemi kit, or a build yourself EFI kit from megasquirt. These all have different advantages, and drawbacks. There is TONS of info in the swap section about it... I chose the FAST XFI system for its self tuning abilities. I love the way its set-up, and how it runs with this system, however, there are now options that do similar cheaper that wernt on the market when I purchased. If I could do it over Id do the factory ECU and be on the road quicker..

 

[joeboy]

PART 2


Next question, Fuel system if EFI, 3/8 line needing 58 PSI, your chioce in-tank or not for the pump, and fuel regulation. Cheapest is out of tank, quietest and most road worthy is in tank... rockvalleyauto or someplace like taht sells a drop in unit that welds into the factory tank, thats what I used. speedway motors sells a LT1 swap pump and connectors that is a good option too. Most guys use a 99 corvette fuel filter, it has a built in regulator at 58 PSI, and takes care of the return line out too... multiple threads about this set-up too..

The next engine hurdle is accessories, the truck timing cover fits them easily, the car cover puts the ALT really close to the passenger frame rail, I trimmed the frame lip for mine to fit. Most delete power steering, however TTI says they have headers for the borgensen power box, NOT factory box... The above companies make PS delete stuff for belt routing. The AC is doable, but I dont know much about that. The radiator, hoses, elec fan and remote oil filter are all little headaches...

Transmission: The Hemi bolts to a SB trans, you just need a different flex plate or flywheel available from mopar or mancini. I would plan on beefing up a 904 to handle the power. The rest is all how you wanna do it, parts are available from multiple vendors. The 545RFE from the 2wd Hemi trucks works great for the swap and can use the factory ECU, however major floor surgery is required.The factory hemi car trans are really not usable due to programming problems with ABS and VSS sensors and the ECUs. As far as 5spd, Id look at passions 855OD, the R154 "supra trans" or a T56. Theres threads about all of these options, all excepts the passion trans will require floor mods. I run a 727 for now, and will swap to a OD (200r4) next yr hopefully.

Not sure which rear you have, I'd say most guys swap to a 8.75, I'm sure a 8.25 could be made to handle the power, I doubt a 7.25 would handle any abuse at all. But I've never ran anything but a 8.75, so I know little about the others...


Thats the basics, there is so much info on FABO, it is literally the BEST place for these swaps, lots of reading, and slowly build what ya can get your hands on.

 

[73dartswing]

Thank you for all that joeboy. I will do my best to keep updates on progress.

 

[Rat Patrol]

You wont have guard clearance issues if you use a JEEP alt instead of a car one - the Jeep alts bolt from the front, not the side, and sit a little higher.

Both the 5.7 and 6.1 timing covers have provision for both types.

 

[73dartswing]

Alright so I didn't do the swap before my was but I trailered it to Chicago and got an awesome deal on a fresh 440 and 727 transmission and decided to go that route instead.
I used the Schumacher mounts and they worked perfect.
Used stock hp manifolds from a b and c body in order to clear the fenders and steering column until I can afford the Schumacher headers.
Bought the Mopar max wedge dual pane intake manifold off summit racing.
Had to buy a mid sump oil pan and pickup tube to fit around the stock k member.
I'm using an old holly 750 for the carb that I got from a car parts hoarder for cheap and rebuilt.

I modified the 904 k member to fit the 727 but I got it to work.
Had to get a custom drives haft built because the 727 was out of a 4x4 truck and didn't have a slip yoke.

Haven't gotten to drive it but it sounds pretty nasty and should be fun.

I'm in school now around 1000 miles away at wyotech so it's only being worked on during the few days I have off between classes. Hopefully during the next break I'll be able to drive it out here and work on it in my classes.