5.7 in 4-speed 64 dart

[hydro]

Bakaruda, Is that a truck motor in your sig pic?

I'm planning to start on a '71 Duster Twister project this summer and am thinking of going the XV computer/manifold/carb direction. The discussions above about the head porting and cam swap look like a good idea as long as I'm this early in the planning stages, and the end use for the car will be mostly street/road use with 400 HP or so at the rear wheels as a target. I'll probably go with a newer overdrive automatic transmission and just modify the car to make it fit (I like to do fab work!), and I have either 3.23 or 3.91 gears as options. Ideally I would like to have AC in the car so the compressor mounting and hood clearance is a consideration.

Keep up the information This is great stuff!

[USCG Charger]

I agree with bakaruda...... for the most part every hot rod shop is gonna tell you a few different things that might or might not work w/ur application. I too am do a street rod and fully expect it to have close to 600hp and rev up very fast.... my biggest difference w/most of these giys on here thats doing it is the EFI vs carb... I setting mine up for carb use and maybe down the road I'll run the EFI.
JAson

[Bakaruda]

Yes I am using a truck motor. I am going to have some head work done and do a cam. I would like to run larger injectors as well. For now they are somewhat limited.

[DRJDVM95]

This is kinda late in the whole drama of this discussion but...

So am I reading this right........ the general concensus is to just use a 5.7 motor rather than a 6.1 ??

I'm building a forced induction motor (hopefully a turbo but if not a procharger) for a 70 Barracuda. My goal is around 800 HP. I have "junk" 5.7 longblock (its got a spun bearing) w/o all the accesories for all my mock-up, but was planning on using a 6.1 for the actual build..

So would I be better off just using the 5.7 ?? I'm gonna replace all the internals anyway, even if its a 6.1...

I thought the actual block design was slightly different too....not just the oil squirters stuff...

[USCG Charger]

I would just do what I'm doing.... I have a used 5.7L truck block: I fully expect my build to have in up wards of 600hp... its a 5.7L stroked to 383....
4" bore
custom CP forged pistons
carrillo forged rods
forged 6.1L crank
manley valves
ported heads
TTi headers and motor mounts
weldtech custom oil pan and block off plate
650-750 carb (not sure which one)
mopar intake
reverse manual VB 727
narrowed 8.75 (3.91 GRS)
tq trust 15x10 wheels

[CudaSRT8]

DRJ,
If you're building a '70 (E-body) model, you won't have anywhere near the challenges we A-body guys have.   I'm not an engine guru, so I won't even begin to try and tell you which block to build (5.7 or 6.1), but the outside of the block and heads are the same and either one will bolt into a stock suspension E-body with ease using the TTI mounts or the S&P mounts.

The big concern with the A-bodies is they're several inches narrower between the frame rails than an E-body, so we don't have the same room when trying to use the car (vs. truck) front timing cover.  The pass. car cover mounts the alternator and AC pump way down low where they conflict with the frame rail (pass. side) and engine mount tower and mount (driver side).  By comparison, you'll have tons of room.

There are numerous, absolutely beautiful, completed and running E-bodies out there with 6.1s in them.    If you want to stay with stock K member and suspension, I recommend talking with Mark (owner) at S&P.  They've built several E and B bodies that way.   

If you want to go with the AlterKtion, talk with Dave (owner) at Modern Muscle.   Treat your eyes to an incredibly gorgeous car by checking out Dave's 70 Challenger with a 6.1 in it (he used the AlterKtion).   His website is (henrycorods.com) .   

Keep us posted on your decisions and progress.   Some of us Gen3 Hemi guys are addicted to this stuff and can't get enough   

[DavidBrenner]

Keep us posted on your decisions and progress.   Some of us Gen3 Hemi guys are addicted to this stuff and can't get enough   

[DRJDVM95]

Thanks for the reply guys..

I'm not worried or questioning how things are gonna fit.... I already have an Alterkations frame and the 5.7 in mocked up sitting in the car. I know all about the actual conversion etc for the e-body.

My question is more about the ability for the block to withstand high HP.....in other words, if I'm building an 800+ HP motor with FI, is is really better to go with a 6.1 block, or just use the 5.7??.....all the internal components in either case will be forged etc and buit for FI application. So consider the internals a wash in comparing the 5.7 vs 6.1 in this case.....

Obviously 6.1 blocks are much harder to find, but if the 6.1 block has a better chance to survive high HP loads, I'll get one...

The book New HEMI Builders Guide says the bulkheads are different in the 5.7 vs 6.1, plus the oil "squirters" for the pistons....

[Joe-Dokes]

DRJDVM95,

From what I've been reading both blocks are essentially the same.  The only difference is the bore.  The resulting bore of the 6.1 is such that there is not much room for an overbore, max overbore seems to be .020.  Thus if you are forced to do multiple rebuilds the 5.7 may actually be superior.  Both blocks at or near factory bores seem to very strong with cross bolted main caps.  Since you said consider the internals a wash.  You'd probably just go with a 5.7 block.     

In terms of Crank, Rods, Pistons. 

The stock pistons on both motors appear to be particularly problematic for high horsepower applications.  There are three reasons, first the top ring is extremely close to the top of the piston, so it takes a beating from any power adder, according to a friend who works at a Dodge dealership he has seen a large number of SRT/8 Chargers come in with damaged motors in which the owner either added NOS or a Blower and it pinched the top ring causing a burnt/scuffed piston cylinder.  The second reason, is the ring itself is a very thin ring designed primarily to give less drag and higher fuel economy.ag Third, the piston is a very short skirt design with a very long rod, again it appears as though the engineers were designing the hemi to have as little parasitic loss as possible. 

The rods on the 6.1 are factory forged units.  As far as their reliability in high horsepower application, I believe they are the same rods used in the 392 525/540 Gen III hemi.  Good for 600 Hp, probably, good for 800 Hp?  Don't know?  At that level Carrillo rods would probably be cheap insurance.

The 5.7 rods are powdered metal and according to Hot Rod Magazine and Popular Hot Rodding, they are at the limit at about 500 flywheel horsepower. 

The 6.1 Hemi uses a forged crank while the 5.7 uses a cast crank.  I think the cast unit is probably good for 500-600 flywheel hp. but for more than that you'd want to used a forged unit.  In addition at that power level you would probably be using some form of stroker crank, either an offset ground or after market forged unit.  In either case a forging would be mandatory.

I think the final answer to your question is what is cheaper in both the short and long run.

If you went the 5.7 route you'd need to replace all the internals, crank, rods, pistons.  With the 6.1 you could probably keep the crank, and maybe the rods.  As far as the cylinder heads go, I honestly believe the 6.1 are better, and they would probably need less work as well. 

So the question is can you get the 6.1 long block cheap enough to cover the premium over a 5.7.  You can pick up a complete 5.7 all day long for $2000.00 to $2500.00 (people have been claiming cheaper but I haven't seen them for much less than 2K), while the 6.1 will set you back double that.  So can you do your head work on the 5.7 heads and replace the crank and rods on your 5.7 for about $2500.00?  I think it'd be pretty close.   

Here's a slightly different question.

I saw a t56 six speed transmission out of a Dodge Viper on ebay.  I know that it would take major tunnel surgery to get that into an A-Body.  That being said, would the t56 with the viper bell housing bolt up?

A new Tremec is about 2K, Keisler sells a Tremec kit for over 5K.  Needless to say, something cheaper would be better

The reason that I ask, is that I've been bench racing about ten different ideas for Gen III hemi installs, ie. 727, 904, 518 or 545.  833 Tremec TKO 600, or T 56.

Someone please correct me if I wrong here.  The Viper V-10 motor has a small block LA bolt pattern, correct?  The Gen III Hemi has an LA bolt pattern minus the top bolt, correct?  Thus, since I can buy a 130 tooth flywheel for the hemi and a clutch wouldn't the t56 just bolt up?

Thanks

Regards

Joe Dokes

[CudaSRT8]

DRJ,
Sounds like you've come quite aways on your build then.   Congrats on the AlterKtion.   Good way to go; that's what I ended up doing. 

Can't answer your question through my own personal experience.   Can just offer what intel  I've gathered over the last few years.   I read in actual Chrysler bulletins that the 6.1 block was beefed up over the 5.7, so my tendancy would be to use the 6.1 for build up. 

You might check with Lee at Frank's Racing for his input.   He seems to be strongly opinionated that the 5.7 is the way to go.   However, I've HEARD that he only has a couple of actual, complete engine builds out there.    I'm pretty sure that Stu at Hemi Shop has been working with the Gen3 Hemi longer and again, I've HEARD that Hemi Shop has more like 20-30 engines under their belt.   

Personally, I'm pretty impressed with what I've seen coming out of Arrington and I will probably be leaning toward them to trust my hard earned, 6.1 parts with.

By the way, while checking out Dave's Challenger at Modern Muscle website, also click on "Justin's Cuda" for a real trick 71 Cuda.   Justin works at Arrington and the Cuda has a pretty trick Gen3 in it.  The Modern Muscle website has the most pictures of the car, but Arrington's website has more data on the car / engine...

[Bakaruda]

One thing I would add to the SRT8 motor's having burned pistons is fuel issues. What I mean is they go,lean when you get of the pedal. So if you are under boost then let up hard the fuel is removed fast and boom. One fix I read about was to tap the fule rails and run a return to the tank. This will help with constant preasure to the injectors. I do not like the big stroker motors due to the short piston skirt. The top ring is in the piston pin area. I like the 6.1 stroke crank and custom rods with custom pistons. Now every one your turn to disagree with me. 

[Joe-Dokes]

Bakaruda,

The lean condition makes a lot of sense.  Thanks for the information.

Regards

Joe Dokes

[USCG Charger]

One thing I would add to the SRT8 motor's having burned pistons is fuel issues. What I mean is they go,lean when you get of the pedal. So if you are under boost then let up hard the fuel is removed fast and boom. One fix I read about was to tap the fule rails and run a return to the tank. This will help with constant preasure to the injectors. I do not like the big stroker motors due to the short piston skirt. The top ring is in the piston pin area. I like the 6.1 stroke crank and custom rods with custom pistons. Now every one your turn to disagree with me. 

Bakaruda,

I don't dissagree at all... mine is that way.. I have custom forged pistons, w/custom carrillo rods, and a offset grind 6.1 crank..... the weakest part of these Hemis is their pistons... u need to replace them asap if u plan on running anything other than stock heads and cam.

Jason

[DavidBrenner]

One thing I would add to the SRT8 motor's having burned pistons is fuel issues. What I mean is they go,lean when you get of the pedal. So if you are under boost then let up hard the fuel is removed fast and boom. One fix I read about was to tap the fule rails and run a return to the tank. This will help with constant preasure to the injectors. I do not like the big stroker motors due to the short piston skirt. The top ring is in the piston pin area. I like the 6.1 stroke crank and custom rods with custom pistons. Now every one your turn to disagree with me. 

Bakaruda,

I don't dissagree at all... mine is that way.. I have custom forged pistons, w/custom carrillo rods, and a offset grind 6.1 crank..... the weakest part of these Hemis is their pistons... u need to replace them asap if u plan on running anything other than stock heads and cam.

Jason

Are you guys saying I should even consider a different piston? I was thinking about running a little cam, (Sidewinder @ 526/526, 212/212, 114 LSA +4) and doing a tiny bit of head work. Max HP in the 450 range. As I understand it, I should at least open up the ring end gap a bit. Am I wrong.

[DavidBrenner]

It looks like I found another differance between the truck and car motors. The truck motors have a 7 rib serpentine belt and the car has a 6 rib. I had planned to change the front cover of my car motor to the truck cover. It looks like I need to add a harmonic balancer to the list.
I might find it better to sell or trade my brand new 2008 car motor and find a truck motor. I all ready have the water pump and cover for the truck. Still need the A/C compressor, idier pulleys, tentioner, and balancer.

[CudaSRT8]

David,
Yeah, the car serpentine system is 6 ribs and the truck system is 7.  Evidenty the 7 rib (wider belt) is considered a little more HD for the trucks?  I bought an ATI damper for my engine which isn't cheap, but a stock damper isn't too bad (I think about $100).   Thinking back on my purchases, "ballpark " costs for your front accessories (OEM new and will depend on cooperative parts guy):

AC comp:  300-350
PS pump:  150
Alternator : 150

You'll need the modifications to the front cover and the bracketry to be able to mount the accessories to the truck cover while using the car intake manifold.   In your shoes, I personally would go with the Hemi Shop bracketry and not fool with trying to swap or get another engine.   

OR, let me make the following suggestion:

The car and truck accessories are different parts as everything pretty much mounts differently.  You will need to make these purchases either way, no matter which way you go.   Before you start trying to find another engine, or sell your current one, or do a swap, just go get a new truck intake.   It will bolt up and that will be that.   I'm pretty sure the throttle bodies are interchangeable, but you'd have to double check on that.   I'll bet that manifold is not all that expensive, or for that matter, you could probably find a good used one real cheap.

Another option:  get yourself a MP aluminum intake or the XV intake.   Would then need a new four throat throttle body.  I recently saw a MP manifold on ebay.   It had been taken off a MP crate engine.   The auction may still be active.       

One last suggestion:
Set up an Excel spreadsheet and plot out the cost for the various options you have.   I did that at one point, early on and it helped alot with my decision making process...

[CudaSRT8]

I'm no engine guru, but here's my take on pistons for these Gen3s:

The 5.7 was built with the latest technology pistons to be a good performing, high production engine, aimed for general use for 100-150K miles.
The 6.1  "     "     "      "        "         "        "           "         higher performing,  "      "       "         "         "         "         "         "        "       "  .
Even the general production Mopar engines of the 60s would give you problems if you started racing them hard, especially with blowers and turbos.  The hot setup back then was to use a forged, TRW piston whose part number became almost iconic among engine builders and Mopar enthusiasts. 

Now we have NOS, blowers, turbos, etc. and OF COURSE we're going to have problems with stock pistons if we use power adders and drive them real hard.   There are pistons available out there now for these engines that are a little more like that old TRW piston with regard to rings, ring lands, distances, etc.   

I'm only going to be racing my car at a track once or twice a year and I'll probably only make maybe 6 passes each time.   I can't help but think my stock pistons and bottom end will be fine...   

[DavidBrenner]

One last suggestion:
Set up an Excel spreadsheet and plot out the cost for the various options you have.   I did that at one point, early on and it helped alot with my decision making process...

You don't still have that spreadsheet do you?

[Joe-Dokes]

Cuda SRT8,

Great idea with the spread sheet.  I've been bench racing so many ideas that I can't keep them all straight.  This will help quantify my decisions making process.

Regards,

Joe Dokes

[CudaSRT8]

Don't have the spreadsheet set up anymore, but it's real easy to set up.   Across the top of your columns would be the main, total engine choice combos that you can think of.  You could include tranny choices in those combos if you want. 

Down the far left column is all the components that it would take to create the engine combo.  Under each column heading (engine/tranny combo), you start going down and plug in the cost of each component that in the left column.    When all those numbers are plugged in, you add up each column and see what the total cost of each combo is.   

It's easy to be a little in denial as to how much something like this is going to cost.   We'd prefer to think we can find ways to do a lot of it cheaply.   By putting on paper, the truth pretty much comes out.   It can be a real eye opener once you really organize the numbers...

[DavidBrenner]

found this on Ebay
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=220189312742&ssPageName=ADME:B:EF:MOTORS:1123

[Alexandre_Garcia]

Joe-Dokes,

The Viper tranny bolt pattern will not fit the LA like 5.7/6.1 bolt pattern. You'll need a bellhousing or scattershield for the Hemi (the LA ones works) and will have to mate the viper tranny to it.

[flyboy01]

found this on Ebay
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=220189312742&ssPageName=ADME:B:EF:MOTORS:1123

Me likes.

[Ruster]

Hi all,  this is my first post here but I was reading this thread and there is some real good info in this thread that I wasn't previously aware of but theres also some plain wrong info too.  I'm definately going to be PM'n a few of you with more detailed questions as I'm in the middle of a new hemi into an a body mopar install myself but not so far allong that I can't make some changes.  After reading this thread I had to join the forum.  I'm leaning toward the 6.1 intake manifold as my engine is  6.1 baised but I really want to use the car timing cover settup with the stock K member (I've got a thing for the stock torsion bars) and am curious just how bad the interfearance issues are?  Does anyone have any pics of the problem?  I can do the truck cover conversion settup pretty easily if it will work but would rather use the car accessories, even if I have to make a few mods.  Also, I'm not sure the alternator and AC compressor will clear the stock hood with the conversion kit but it could probablly be adapted if it turns out thats the only way.

[DavidBrenner]

It is my understanding that the Alt. may require some frame grinding and replating. The A/C compressor interfers with the spool type motor mount by about 3" . I have heard about someone cuting the mount and making other arangments there. Running the TTI headers requires cuting off an ear the the compressor AND dinging one of the header tubes.
All of this is hearsay and I don't know first hand. I have put my parts collecting on hold untill more is PROVEN and maybe the cost of the electronic comes down some. OR I make lot more money than expected and can't help myself. One thing for sure is that the Hemi will go in someday. I am just tring to be smart about it this time around and not just throw money at everything this time.

[Ruster]

So it sounds like a little work can get the alt in.  The AC I could initially deleate and run some type of short belt settup.  Also I have the old spacer type motor mounts not the spools.  I'll try a tryal fit and see for myself and report.

[CudaSRT8]

Ruster,
Welcome to the site.   I joined this site when I intended to drop a 440 six pack in my cuda.   However, I fell in love with the new Hemi and haven't looked back since.   I've done considerable research in the process of putting a Gen3 Hemi in my car.  My build "mock up" is pretty much complete and I'm now in the process of welding up engine bay holes that will not be used. 

I'll answer as many of your questions as I can, but only the ones I KNOW by my own experience.   Given the long road this has been for me, I'm happy to help anyone who is just starting this venture and save them any time, mistakes and money that I can.  However, the big thing I've noticed is all the variable wants and needs that everyone has for putting in a Gen3.   Some people want stock susp. like you do (and I did when I first started); some people want an 833 4 speed;  some want Tremec 5 or 6 speed;  some want 727 or 904 TF;  some want an automatic w/OD.   These variables change many aspects of the swap and some people will have to forge ahead on their own to find the answers.       

As you noticed, some of the input on this thread has been wrong or just hearsay.  Let me QUALIFY my input by stating my actual references and experience so far:
I studied several converted cars at the '05 SEMA show, talked to the owners and took pictures.   
I have a MP 5.7 FI crate engine (probably going to sell this engine)
I have a 6.1 SRT8 engine 
I have a Tremec 5 speed
I have stock suspension (now removed)
I now have the AlterKtion suspension
I have the AlterK / TTI headers for the 6.1
I have the MP engine harness, ECU and cable throttle body
The dealer I use has allowed me to experiment with new, factory parts for my conversion and return the parts that don't work (this has been a real blessing and allowed me to experiment without concern for cost).

I first started putting the 5.7 crate engine in (which has the truck front cover) using a stock suspension, TTI mount kit and TTI headers.  This combination bolts in, but I did not like the "fit".   For that matter, the left torsion bar would not fit with the header in place (by approx 1/4").  I would have had to dent the header in 2 places to put it together.   The fit around the steering box was also very tight and would have likely hit the header tube at some point or another when the car was up and running.  In my view, TTI made a valiant effort, but I was not willing to settle for the fit. 

I also trial fitted the 6.1 engine with stock suspension (car front cover and accessories).  The right frame rail would need to be notched roughly 1" square by 8" long to clear the alternator.   The AC pump would not clear the engine mount stand and mount (bisquit type).   From what I remember, I think the #1 header tube also interfered and possibly even the steering box.   Bottom line, you're trying to fit an AC pump down where there's already a bunch of other stuff!   I highly recommend trying the Hemi Shop kit for using the truck cover / accessories with the 6.1 intake.  When I was going to use the 5.7 crate engine, I know there was no concern about hood clearance.   Unless the kit RAISES the alt. and pump, I would think it will still clear the hood.  (Let us know on that.) 

Ruster, what transmission do you intend to use?  

[gocirino]

68 Dart 6.1 pix including the wire harness computers (FAST) and the in tank fuel pump and return.

[jeffneal66]

Hey that looks great, you are well into the fit-up process!  It also looks like the alternator is mounted low near the frame rail, how does that work?

Jeff