5.7 Hemi Advice

[Bruceynz]

Hi Guys,

My friend has a 1969 Dodge Dart coupe (its an aussie RHD one called a Chrysler Valiant) He is going to repower it with a late model Eagle head 5.7 Hemi. (I think its a 2014 engine)

This is his combo:


Alloy intake with a carb - unknown size maybe 750cfm or there abouts
218/225 at 50 thou on a 114 LSA
Stock Stall Converter
3.23 Rear end ratio
727 Small block trans



Whats it going to go like on the stock converter? What is the whole setup going to go like?

The 114 LSA will flatten it out, but not sure how it will effect the bottom end, will the cam make it a bit sluggish off line or will the wider LSA help it out a bit?

Thanks
Bruce

 

[BudW]

Will it be a North America engine?

The early 5.7L engines are different from Later ones (actually, there might be a few different versions of 5.7L over the years). The 2014 version should have VVT (variable valve timing) which affects most everything as far as camshaft specs go.

Most of the 5.7L Hemi’s have wild camshaft specifications - but also behave very well at idle and low speeds (the best of both worlds) – but the mechanics (and electronics) behind that is not something to retrofit to an older engine.

Changing camshaft specifications on a VVT engine will mess with the computer (a lot), so a camshaft change on a VVT will, in most cases, be counter-productive, unless you have someone with access to re-program the engine computer accordingly.

Most of the people I know with the 5.7, 6.1 or 6.4L Hemi’s have left the camshaft alone with them.
BudW

 

[Bruceynz]

Its going to have a carb and a MSD6 or something ignition controller, you change the cam and lifters and the VVT is gone, you change the relutcor wheel inside the engine to an earlier one for the MSD6 to work.

 

[BudW]

If getting rid of the VVT, then yes, the old camshaft specifications then jump back into play.

 

[Bruceynz]

Will his spec cam be ok on a stock 1970's small block 727 torque converter and 3.23? AJ Forms where are you, your good at the math behind this and cylinder pressures.

 

[MoparKidD-4]

Probably not... late-model Hemis have ports almost as big as the old 426 but they're feeding only 345 cubes, hence the excellent power output. But this also magnifies the effect of valve overlap from a bigger cam; the same specs that would run mild enough for the street in an old wedge head small block will make a 5.7L lose a ton of bottom end, which they don't have a whole lot of to begin with (relatively). Just a guess but it will probably need at least 3.55 gears and a 2800 RPM stall converter.

I have a 2014 5.7L sitting on a stand in my garage someday to go into my '70 Duster. Someday because I plan to run the Mopar engine controller setup with the factory EFI which is about $1400 retail, and it needs a new cam as the stock one has a trashed lobe; as far as I know, only COMP currently offers a line of cams for the 2009-up Hemis which is different from the older models even with a phaser-limiting kit, also required with the COMP which altogether is close to $1000, probably not including the new lifters to delete the MDS. I think if your friend has the money to do one of these swaps properly he should build up the drivetrain to match...

 

[Bruceynz]

so with his 3.23 gears, stock 1970s stall small bock 727 and the cam he is going to run he will build a car that is slow off the line?

 

[4speedjim]

HEY that thing got a HEMI? Is it a bullet or a a slug:<( What can I say, Im an American. The best advice IMO is build it to factory stock. Its 400/400 hp/tq rolling off the line! Assembly line that is. Now that in an A body is a bullet. It'll twist that A body like a pretzel w/out a cage! Cubic Dollars to equal that as non stock build. The wheels already been been perfected. Dont waste time and cubic dollars. Get the cpu, actually a standard trans cpu so the cpu isnt looking for the automatic it probably had, fuel pump, intake, and all the harness and sensors. And the alt or a big aftermarket. The alt original to the car will never power it. Thats my thought Bruce. We can ship ya good used, whatever you cant find.

 

[BudW]

I would have to agree, the new 5.7, 6.1L, 6.2L or 6.4L Hemi’s are probably best to leave alone (or stock) – especially with an engine the VVT.
The MDS (Multiple Displacement System) might be a good idea to delete/disable – if wanted (not going to hurt anything with it on or off and will give better fuel mileage).

A manual transmission CPU is a must if not using a computer controlled automatic transmission.

IF I was going to do any modifications to the new style Hemi (and not sure why a person would need to) is a supercharger.
BudW

 

[80mirada]

Most of the carb intakes for the gen3 Hemi suck. They work, but they have poor fuel distribution. There is an inexpensive cotroller kit for them, I will try to post the link for it later

 

[MoparKidD-4]

Cubic Dollars... very accurate statement lol! Not like the stinkin' LS crowd they have it easy and cheap.

 

[4speedjim]

The converter is probably 1400=1500 im assuming. With a bone stock 2014 5.7 should be for good, no great for a 2800 pound street car. Since you have the converter, throw it in, you already have it. And Id definitely rebuild the trans with much stronger parts and valve body mods. The HEMI will tare the stock 250 hp 727 to bits.

 

[80mirada]

MS3 Gen3 Hemi Plug & Play Gold Box - EFI Source

Least expensive control kit for those that want to run an injected gen3. They have a lot of options available for it including VVT control

 

[4speedjim]

MS3 Gen3 Hemi Plug & Play Gold Box - EFI Source

Least expensive control kit for those that want to run an injected gen3. They have a lot of options available for it including VVT control

WINNER WINNER CHICKEN DINNER!! That an incredible system for a price leader! Im gonna guess. $2200 USD?

 

[MoparKidD-4]

WINNER WINNER CHICKEN DINNER!! That an incredible system for a price leader! Im gonna guess. $2200 USD?

Um, it says right on the site, $1295... lol. That is a fantastic price, about $100 cheaper than the MP setup but it doesn't mention anything about the drive-by-wire stuff (MP kit comes with a drive-by-wire gas pedal).

 

[BudW]

Whenever I think of drive-by-wire – my mind goes back to the movie Christine (for some odd reason).
BudW

 

[4speedjim]

I guess I didnt looking hard enough. I was just totally blown away with that pkg for a Mopar. Last I looked some wizard was using junk yard GM 0411 cpu i believe and you used your own MS1 IIRC to drive the ignition to power the new Hemi. That was $2500+ an extra $1000 for the harness. He kept it all close to his vest understandably. I was fortunate enough to overhear the cpu he used. It was BASIC engine only and not emission compliant.

 

[MoparKidD-4]

I guess I didnt looking hard enough. I was just totally blown away with that pkg for a Mopar. Last I looked some wizard was using junk yard GM 0411 cpu i believe and you used your own MS1 IIRC to drive the ignition to power the new Hemi. That was $2500+ an extra $1000 for the harness. He kept it all close to his vest understandably. I was fortunate enough to overhear the cpu he used. It was BASIC engine only and not emission compliant.

I get where you're coming from, the aftermarket has really opened up for the Gen3 Hemis just in the past 5 years or so; before that it was total DIY and/or spend $2000+ on a custom fuel and spark management system. It's still an expensive road to travel putting a new Hemi in an old Mopar but it's getting easier as time goes on. Shoot, right at this moment I see an ad at the bottom of this page for new Edelbrock aluminum Gen3 Hemi heads which were released just in the past few months.

I just wish it was a bit more "modular" like the LS, GM has had so many different versions of that engine powering all kinds of vehicles for what, 20 years now? Guys are now picking up junkyard 4.8L and 5.3L truck LS engines, slapping on a turbo system and pushing 1000+ HP. Chrysler never made a "lesser" version of the Hemi which adds to the cool factor but makes them that much more expensive. BUT at the end of the day, even pro engine builders agree the modern Hemi is a better design as far as making power in factory form.