Got a 70 dart planning on this winter when money gets right.Putting newer hemi in it .Which one at junk yard should i be looking for one out of a truck or car?

I would get an early truck hemi without the mds. All hemis that came in the magnum's, 300's, and charger's had mds.

How early what years do you suggest?

I believe the mds in the trucks was introduced in 07. Might be 06, though. Can someone clarify this? I also wasn't specific enough before, the 5.7 hemis in the cars all have mds but the 6.1 hemis do not.

Why wouldn't you want the MDS? The auto industry needs to put similar systems on every engine, not just V8's. Why not take advantage of a little fuel milage in the A-body?

Personally, I drive muscle cars for the muscle not economy and if I were swapping a HEMI into my car it would be all for the power not extra MPG.

With today's technology you can have your cake and eat it too. I'm restoring my dad's 73 Challenger and am worried about spending this much money on the car with gas prices so high.

The MDS only kicks in while cruising. It has no effect on HP.

Why not use it if it's available? I drive my muscle cars for the muscle as well, but the time I actually USE that aspect of the car is MAYBE 1% of the time, being very generous. Granted, the time that I might be in the right parameters to engage the MDS might not be very frequent either, but I'd wager that it would be more often than WOT. I'd personally hate to leave any economy on the table, for those times that I'm driving to an autocross event, or cruising with my family out to the lake with the top down. If there's some reason that it renders the salvage engine inop, that's one thing, but I can't imagine that's the case.

Clair

I know it only works while cruising but all I am saying is personally I would like all cylinders firing at all times and I would probably swap a carb. onto it as well. But if gtx69 wants mds then any year HEMI that came in a car will do.

To my way of thinking the only reason to not have the MDS is that it pretty much locks you into the factory electronics.

I'd look for a Hemi with the type of transmission you want.

R.

I'm going to keep my eye out for a wrecked one that way i can get trans also.Don't matter if auto or stick since this will be a winter project i got a few months to go.

mds or no mds...does not matter. all the hemis and that includes the 6.1 have the provision for it.
use the early truck or 6.1 mds plugs and get rid of the solenoid if its not wanted or needed.

mds wont work even if you use anything over a 20 weight motor oil also.

what concerns me is the chasis. the truck uses a high mount alt and a/c compressor.

the auto stuff is low and on the side.

check your chasis and see if one works better than the other. i prefer the car motor myself.

the cars use a much better intake manifold.


steve

mds uses too much information to activate it. you would have a wiring nightmare i think to get it operational. the lx cars themselves have 7 computers. each talking to each other.

the mds system uses oil pressure..oil temp...water temp...pressure on the throttle...vacuum reading..
just to name a few that need to be met to initiate its operation.

heck...they even set codes if the motor does not come up to temp fast these days. so adding low temp thermostats can be tricky at times.

if it was me, i would forgo the factory computer and run the motor without the mds ect..
they really are a nice engine that can make good power.




steve

i would recommend an 04 manual trans 2500 Dodge ram PCM. You do not have to worry about limp in mode with a manudal trans controller. A truck engine will fit in an a-body. One concern is the back of the intake is basically resting on the firewall/bulkhead. The alternator and compressor will clear the hood though. The car manifold is suppose to be better flow, and the no spark plug wires looks a little bit better on the later cars.

Good luck...

I have no experience with the MDS on a swap, so I cant give any advice there!

Justin

Gremlinsteve,
What is the ultimate control of the MDS? I think I read that it is some sort of oil control to half the lifters, but I gotta confess that I really don't know much about the system. Obviously, there has to be some control of the injectors firing in to the disabled cylinders as well. I can forsee an "alternative" EFI controller being able to operate the MDS in a stone-axe kind of way, maybe in the same kind of way that folks are making the lockup and OD work on 518's. Not exactly the same of course, but basically a low-tech way of achieving the same end.

What are your thoughts on kludging your way to MDS if all the operatinal parts are in place?

Clair

a solenoid. its dropped in from the "lifter" valley area on these motors. remove the intake manifold on these motors, its dry so no coolant sees it, and you will see four plugs.

these plugs, again, are either plugged or use a solenoid. cyl 1 and 7 along with cyl 4 and 6 are mds. the solenoid dropps pressure to the lifter. the

the exhaust valve is cracked open using the system and the intake remains closed.

the computer drops the injector for the mds cyl at the same time.

its a very complicated system and only works on a stock computer. obviously.

again. the system reads alot of information that has to be met before it works.

if you change oil in the car amd move to 30 weight from the standard advised 20 weight oil, the syetm will not operate.

i have pics if interested.

steve

and again. wether you use a truck or car 5.7 or 6.1 depends on where you want or need the accessories placed in the chasis.

i prefer the 5.7 car intake. using it on a truck platform will give you grief tho.

a 6.1 intake can be adapted to a truck accesory drive tho. but in our testing. the 5.7 car intake on a 5.7 modded car motor out performed the 6.1 intake across the curve.

some have tested and shown slight increases tho.

i still prefer a carb intake and go from there..


steve

the truck style coil packs from the earlier years can be changed over to the newer style dual plug on single coil system. its a much cleaner look. lets you lose the long plug wires.

kits run in the 300-350 range.


comes with eight coil packs. the valve covers..pig tail ect..everything one would need.

steve

Wow, that's a little more complex than I had visualized. That's the problem with the OE's, they really put a lot of work in to making something work... and work well. Good info!

Clair

i am swapping every piece I can swap from a wrecked 07 Charger R/T to a 1970 GTX. The GTX goes to the paint stripper on Tuesday. The 5.7 came out of the donor car with ALL of the harness intact....very easy "plug-in" harness! I cannot say what "issues" will come up yet but our intent is to put everything in the GTX just like it came out of the donor car. I am POSITIVE we will encounter some curves, i.e. override ABS system for one,and who knows what else. The plan is to get it running as stock as we can then start tweaking it. The only drive train piece we won't be doing is the independent rear suspension (Air Ride 4 link w coil overs).I think this approach will be easiest not counting getting everything mounted in a reasonable way. The 5.7 will sit in an Alterktion instead of a "K" frame so the only clearance issues appear to be the oil pan.
Wath my thread "major Score" on the general Discussion section for ongoing updates. We have some rust issues (imagine that) to deal with first so it will be a little bit but this project is moving right along.
Got the wreck from copart for what I thought was a real good deal considered it still ran and drove.