School me on new gen hemis

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wardy

wardy

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Ok, down here in Australia the newer gen hemi's are about as common as finding a leprechaun riding a unicorn bareback... And if you can find one you have to re finance your house!

But I've been intrigued lately and was thinking instead of buying an aftermarket LA block to build (around $3k landed) I'd almost be better off doing something a little left field and going with a hemi..

I'm building my car, a 68 valiant sedan, to compete on Australian x275 racing, it's currently being pieces together with a single turbo 360LA on e85 that should put out around the 700hp mark..

Basically I want to know the ins and outs of these engines. What years are regarded as the best? 6.1,5.7,6.4 etc?? Are some blocks stronger then others? Do certain heads flow better? I understand some of the newer ones have VCT?
Can a full programmable ecu be used to run them? Can you easily fit up common transmissions to them (powerglide,th400 etc)

I'm open for all types of advice or pointers.. Talk me into it or talk me out of it.
It won't be happening for a while but I'm just doing my research. I'd like to make in the region of 1000wheel hp, 80mm turbo (class rules) and e85.

Fire away :)

Wardy
 
Wardy, sounds like a cool project.
The hemi loves boost , if you get a chance check out :
http://www.cherokeesrt8.com/forums/forumdisplay.php?f=101

They are getting serious power with their jeeps ,even with a T4 based turbo (pt7675). If you are on a budget The T6 s480 borg warner turbo is making great power if you don't mind the 5 inch downpipe.

also check out Stage 6 , they have some combos that are flying with the hemi:
http://www.stage6motorsports.com/s6_07_main.html

I am sure they can point you in the right direction .
 
blown71duster said:
Wardy, sounds like a cool project. The hemi loves boost , if you get a chance check out : http://www.cherokeesrt8.com/forums/forumdisplay.php?f=101 They are getting serious power with their jeeps ,even with a T4 based turbo (pt7675). If you are on a budget The T6 s480 borg warner turbo is making great power if you don't mind the 5 inch downpipe. also check out Stage 6 , they have some combos that are flying with the hemi: http://www.stage6motorsports.com/s6_07_main.html I am sure they can point you in the right direction .
Click to expand...

Hi and thanks for the link! Some great reading in there.. These guys really get these things flying! I actually plan on using the billet wheel s480..

Does anyone else have some info for me? After a few hours research last night I'm leaning towards the 6.1. Forged crank from factory.. Obviously the rest of the rotating assembly will be replaced. Both 5.7 and 6.1 blocks are similar, and have a pretty good design

Heads flow ridiculously well, but have lifting problems over 1000hp? Can anyone confirm is a powerglide or other common automatic be fitted up with an off the shelf adaptor somewhere?

The use of an aftermarket efi is still a bit shady, because I plan on using a different gearbox, aftermarket throttle body on a carb intake and will be rewiring the whole thing, I should be ok
 
Engine Management (computer):
You can run just about any engine management you want. The common computers used for the swap are:
-Megasquirt MS3x (and their rebranded counterparts)
-FAST
-Factory Computer
-LSx computer (with different crank wheel, etc)

Block:
The 5.7 and 6.1 blocks are both very strong. Use ARP main studs (and line hone it with the studs!!). Past 1000 HP billet mains are in order. Cylinder walls are thicker on a 5.7, but the 6.1's haven't had much trouble. The aluminum 6.1 block is the strongest you can get, and may be a good idea if you're building for high hp from the start.

Crank:
6.1 crank is a solid piece. Not sure anyone has broken one. It fits in the 5.7 or the 6.1, so don't go buy a 6.1 just for the crank. Most of the aftermarket manufacturers make a solid piece as well. Not going to advise on what you do there.

Heads:
Aftermarket heads made by thitek for the hemi are a great option for high boost motors (thicker head deck surface). I'm not sure what else is being done to keep the motors sealed at 20+ pounds of boost - some guys o ring the blocks, others are running fancy gaskets, etc. That said, all hemi heads are good with some work. But, for the $$, the Thitek's are probably your best bet if you don't currently own a set of heads.

The motor has the same bellhousing pattern as an LA motor (minus the middle top hole). So, you can bolt it up to anything you can bolt a LA motor to (727/904 is stupid easy). Also, there is a bit of a depth difference, but I don't recall how much (less than 1/2"? - someone help me out here)- that's worth noting for 4 speed standard guys.

There's a member who had a full x275 build planned out - turbofreek. I just sent him a PM. I'm sure he can help you out.

What are the displacement rules for the class?
 
Also check out Turbo forums, they have a mopar specific section . Check out the builds , 5.3-6.0 LS engines running the S475 80 mm turbos. Should be very similar to your build.
Hemi platform very capable of making big power with upgraded short blocks and worked heads.

http://www.theturboforums.com/forum.php
 
Excellent info! Thanks a lot.. Been a member on turbo forums for a while now, trolled there last night and got a bit of an insight.

Basically rules for our x275 down here is:
275 tyre (duh)

Any engine capacity (no raised cams,tall decks etc)

No modified rear chassis rails Max of 80mm turbo inducer.

And a 3200lb weight limit

So that's why I was leaning to a 6.1, with the already 1 piece crank, I'm happy to leave it that capacity..Rods, pistons and complete stud kit with some good head gaskets and a general rebuild and I should be good to go.

I don't need to set the world on fire so I even think the stock heads could work for me if I can keep them down. We also run on a 8.50et index in x275, faster then that and your in outlaw radial.

What is the general asking price for a 5.7/6.1 long engine to suit rebuild? Really only need a bare long engine with alternator, water pump and starter. I plan on using a carb intake with throttle elbow.

And lastly does anyone have one sitting around they would like to sell haha
 
G'day Mate,

ECU wise i dont think you can go past

http://www.efisource.com/shop/ms3-gen3-hemi-plug-play-gold-box/

Uses all factory sesnsors has a base tune in it (for standard engine) 2 rpm limiters, NO2 input, switch between fuel maps, comes with a loom too so makes it piss easy to install, its a no brainer IMO

In Aus I think you may struggle to find an engine, a year or so ago you could buy 6.1 crate engines for a good price and get them shipped over but they're all gone by most accounts.

I'm piecing together a 5.7 hemi turbo also. I was lucky to find a 5.7 on ebay with a few rods out the block, came with all sensors and heads, rocker gear are all re-usable. A mate put me onto another complete standard 5.7 which i can use the block.

Things I've come accros so far:

LA rods appear to fit hemi crank albiet shorter, so using LA rods you can get a custom piston made with a taller comp height to help crown thickness and stability in the bore for boosted application,
If using a 6.1 crank to keep 345 cubes.
Intake manifolds can be reversed so if using an underdash Air to water cooler you can have the throttle body near firewall for nice short intake track.
Bottom end wise there are a few stroker kits around but i'm a little worried about the comp height in the piston, hence the shorter rod with taller comp height, and not sure how long they would last in a boosted app, bore wise and piston skirt wise.

Regarding X275 rules does notching chassis rails for leaf spring hangers/front mounts count as modified rails?
 
2times said:
G'day Mate, ECU wise i dont think you can go past http://www.efisource.com/shop/ms3-gen3-hemi-plug-play-gold-box/ Uses all factory sesnsors has a base tune in it (for standard engine) 2 rpm limiters, NO2 input, switch between fuel maps, comes with a loom too so makes it piss easy to install, its a no brainer IMO In Aus I think you may struggle to find an engine, a year or so ago you could buy 6.1 crate engines for a good price and get them shipped over but they're all gone by most accounts. I'm piecing together a 5.7 hemi turbo also. I was lucky to find a 5.7 on ebay with a few rods out the block, came with all sensors and heads, rocker gear are all re-usable. A mate put me onto another complete standard 5.7 which i can use the block. Things I've come accros so far: LA rods appear to fit hemi crank albiet shorter, so using LA rods you can get a custom piston made with a taller comp height to help crown thickness and stability in the bore for boosted application, If using a 6.1 crank to keep 345 cubes. Intake manifolds can be reversed so if using an underdash Air to water cooler you can have the throttle body near firewall for nice short intake track. Bottom end wise there are a few stroker kits around but i'm a little worried about the comp height in the piston, hence the shorter rod with taller comp height, and not sure how long they would last in a boosted app, bore wise and piston skirt wise. Regarding X275 rules does notching chassis rails for leaf spring hangers/front mounts count as modified rails?
Click to expand...

Hi mate and thanks for the input!

A lot of info I can take on board..

I'll have a look at that ecu, the plug and play is an attractive feature. I was planning to use a haltech ps1000 and wire it all in myself. But that's later down the track.

I was planning on using off the shelf dished pistons and h beams.. Never had a good look at the crown thickness though, I'll have to check that out.

The engines here in aus are ridiculously priced, there are a few around trying to chase $8500aud!!
I'll source and get one shipped over from the states, from what I have seen surely I can get a moderate mileage 6.1 and have it shipped over for a bit under $2k, or am I being too optimistic?

I plan on getting a miloden gen3 hemi to A-body sump, a hemi to powerglide adaptor, the engine of course.. And then have fun fitting it :)
I'll be able to make the power I want quite easily compared to to the small block LA

And yes sorry notched rails are aloud, but must be in standard location.
 
Currently there is a 6.1 block with rotating assembly for sale out of california for 1300 on lxforums.com. I just seen it a minute ago myself. That will have your forged crank already. So go for it.

Thitek heads if you want it reliable at 1000rwhp. The stockers will lift slightly from time to time and could window your investment to zero quickly. However the thitek heads are 3699 a pair but are much better at power and sealing with thicker decks.
That bw s480etr ho is a very nice turbo. Could easily make your car a 4 sec in the 1/8th hotrod.

Powerglide with an sfi bellbousing for a small blck mopar will work. There is a .060 crank offset on the newgen. Mopar makes a flexplate to compensate for this. So not a big deal there.
as for the front accessories good luck. Most dont part with that stuff do to the scarcity of them and the cost. There is a motor plate that will alow a bbc water pumpand other simplier options to use.
stock rocker assemblies are tougher than most. With stock heads you wont run bigger than .580 lift. With thiteks you can run close to .700 lift as well as dual springs etc...

Ive been sick otberwise id type more now. If you have any questions dont be shy.
 
Efi use aftermarket. The stock is a ***** and troublesome with tunes and changes.
I was going ms3x but got a deal on xfi/xim swap kit with v3q dash board logger I couldnt pass up.
 
The Gen III Hemi is truly an amazing motor and the stock cast iron block is amazingly strong. Considering a Ford 302 block will often brake at the 500 HP mark, the Hemi's ability to easily handle double that amount is a tribute to the robustness of the design.

The stock cast iron block can handle up to 1200 HP. However, if you are in a high boost application, keep the stock 3.58" stroke motor. Several stroker kits exist that can increase the stroke from 3.58 to either 4.050" or 4.080" when these kits are combined with superchargers or turbo chargers that produce boost levels in excess of 20 PSI cylinder wall cracking has occurred. This typically only happens in cases where boost is extremely high, over 20 PSI. Basically, if you are going to run high boost, in a stock block, stick to the stock stroke, you can still make in excess of 1000 HP, but you will do so with a 3.58" stroke and 20-25 PSI of boost.

A bored and stroked 6.1L Hemi to 426 cubic inch Hemi will easily handle 8-12 PSI. This assumes that the tune is correct and you don't have a lean condition. As with ANY hot-rodded motor a poor tune with excessively rich, or lean condition can lead to catastrophic failure.

As far as which blocks are stronger. There is a healthy debate regarding the relative merits of 5.7 vs 6.1 blocks. The key benefit of the 6.1 block is the larger bore. It is 4.055" vs. 3.917" for the 5.7L block. Some will argue that the 5.7L block can be bored more than a 6.1L Block, this might be true for some blocks but few if any 5.7L blocks can be bored to 4.055." Keep in mind that according the Chrysler NONE of these blocks can be bored, they are disposable. Now clearly people have been boring both the 5.7L and 6.1L blocks, generally you'll find replacement pistons that are either stock size or .020" larger. Clearly given the relatively thin walls of all Hemi blocks sonic checking is recommended prior to any money being spent boring a block.

As far as heads go. They are all good, but some are better than others. Out of the box 2003-2008 5.7L Hemi heads flow about 260 CFM, while 2009 and later 5.7L Hemi Heads flow about 300 CFM, or about the same as 6.1L Hemi heads. The 6.4L Hemi Heads flow better still, as they have the largest valves. All the heads can be ported to significantly increase performance. The 03-08 heads with stock valves can be ported to flow about 300 CFM, changing valves can get 5.7L heads into the 325 range. 6.1L heads can easily flow 360 CFM. The aftermarket heads and 6.4L heads can be ported to flow nearly 400 CFM.

To put the heads into perspective a full race set of W-5 Heads before porting flow about 270 CFM. So out of the box most Hemi heads are better than a dedicated race head for an LA or Magnum motor.


Regards,

Joe Dokes
 
Joe they have a 3.80 and 3.79 stroker kits for the 5.7s making them a 366 or more depending on bore. My 5.7 cylinders are extremely thick if you compare them to a sb chevy or bbc for that matter. I could actually bore it to 4" but will sacrifice the integrity of the cylinders because they are cast. Unlike old school stuff is ductile iron which makes them more durable still.

I have been told with strokes 3.80 or less 1500-1800 is possible with either block. That is coming from andy at pwr and a few others that build these for a living.
 
thanks a lot joe for the info.. and a big thanks to turbofreek for taking the time pm'ing me and giving me the run down on these engines.

needless to say im getting excited about the swap.. now just to find an engine!

After some thought ill be going the 5.7, mainly due to the initial cost, and the thicker cylinder walls which are more boost friendly. Change the crank over to a 6.1, H-Beams, forged dish top pistons, studs all round and some MLS headgaskets. Maybe a small drop in cam (nothing crazy so the stock heads work ok) With a BorgWarner S480 I should have a fast machine!

if anyone has some contacts for some auto dismantlers (preferably on the west coast) Or has a 5.7 long engine to suit a rebuild they would like to sell let me know :)
 
I've got a 5.7 block (3.937 current, needs another .008 or so to clean up) and 6.1 crank (needs ground or polish) I'd sell. Also have a car front cover with water pump, idler, and tensioner.
Shoot me a PM if interested.
 
turbofreek said:
Joe they have a 3.80 and 3.79 stroker kits for the 5.7s making them a 366 or more depending on bore. My 5.7 cylinders are extremely thick if you compare them to a sb chevy or bbc for that matter. I could actually bore it to 4" but will sacrifice the integrity of the cylinders because they are cast. Unlike old school stuff is ductile iron which makes them more durable still.

I have been told with strokes 3.80 or less 1500-1800 is possible with either block. That is coming from andy at pwr and a few others that build these for a living.
Click to expand...

You are correct, there are stroker kits that utilize a 3.80 stroke crank. This crank in a 6.1L block creates a 392 and is basically what Chrysler did with the 2011 392, they increased the bore to 4.09" and the stroke to 3.72"

The 4.09" bore has a number of advantages. I predict that it will become the preferred hot rod block, mainly because the larger bore allows for a bigger intake valve and the valve pulls away from the cylinder wall faster, which allows for better breathing.

I should have mentioned the 3.80 stroker crank. It has a number of advantages over the popular 4.050" and 4.080" stroker kits. The main one being that it loads the cylinder walls a great deal less.

I am not going to argue with anyone who says they can build a 1500 HP motor based upon a stock block, buuuuuuuut, the level of boost required to make those kinds of numbers has got to be in the 40 PSI range which is ridiculous. I think a motor like that would be a "2 minute" motor. By 2 minute motor I mean that thorough inspection would be required of every component of the motor ever twenty passes or so. I'm basing 40 PSI on the fact that it takes about 20-24 PSI in a 370 cubic inch Hemi to make 1000, if my numbers are off let me know.

I think what is truly amazing is that 750 HP is quiet obtainable on pump gas, this level of power could get a car into the 9s. While 1000-1200 HP is quite doable on race fuel with either turbos or a Kennebell blower, and that 1200 HP is with a fairly mild cam and quite "streetable."

Good Stuff,

Regards,

Joe Dokes
 
Another thing:

Here's the Mopar Performance catalog for Gen III stuff.

[ame]http://www.mopar.com/assets/pdf/performance/catalog/Hemi_Gen_III.pdf[/ame]

Hope you have a fat wallet, their stuff is pricey.

Regards,

Joe Dokes
 
All good advice joe. For sure that power level is something that needs maintenance. Also those hp figures are with heads that only flow 300-350cfm. Add the thiteks with 400 on the smallest head it will drop those boost numbers down to the mid teens. Id guess 22-25psi will be around 14-1600hp with a dedicated real cam and not a mild cam most used with those numbers made. Also the thiteks will allow 700 lift with dual springs on stock rockers unlike the stock heads. Or a set of jesel and skys the limits camshaft size wise. So improvements help those numbers dramatically.

He will be using stock heads will require a significant higher intake restriction reading(boost) to reach his 1000hp goal. Unlike my efforts of going all out with a billlet 88 garrett turbo.
 
I have a Chrysler technical bulletin (sent to dealers) regarding the 6.1 engine when it first came out. I've recently moved and it's buried in a box somewhere, but it specifically compared it to the 5.7 which had already been out for a while. The bottom end area has been beefed/strengthened over the 5.7 and it has piston oil squirters, which I would think might be advantageous with lots of boost (?) (I'm not a boost kind of guy).

I tend to favor the 6.1 block for the above reasons, plus you're already up into the 4 inch plus bore zone. Chrysler says the blocks can be bored up to .020 btw. I believe I read that in a Chrysler 6.1 engine manual (also buried in a box).

There's a number of stroker cranks out there that are not listed on the manufacturer's websites. There's a 3.90ish and a 4.00 I think both Scat and Callies make a 4.00, which is the next one I'm going to use, with either a 4.055 or 4.060 bore (maybe 4.065). I have to work the numbers and see where it would end up, but I think it would be an awesome engine for my Challenger, with plenty of potential for longevity.

Well, there I go thinking NA again. So with boost, I think the 3.795 would be excellent with a stock, or near stock bore 6.1.
 
Cuda, the difference in the bottom of the blocks is the extra bolts on the main cap. They are both still cross bolted mains. Oil squirters are nice but not detrimental. They are designed to cool a piston but more helpful in extreme rpm racing where the pistons dont have time to cool down.
the biggest weakness of all these blocks is the cylinders. That is why I vote 5.7 when one doesnt have a stsrting foundating and cant afford the new Siamese bore aluminum piece. The 5.7 bore is the same as the ls chevy and those we know make massive power with the smaller bore.
stroke effects cylinders. The more stroke the more the piston is shoved into the side of the cylinder wall. Boosted needs to keep the stroke down on a stock block to save the already known weak cylinders. So keep it under 3.80 is best. The 4" stroke is real hard on the walls.
 
Turbofreek,
There's no extra bolts in the mains of a 6.1 over a 5.7. The Chrysler bulletin made it clear the difference was extra, structural "beef". I talked to a lot of Gen3 engine builders when I was looking to build a 6.1 stroker for my Cuda. For NA, non extreme use, they all swore there'd be no problem with the 4.05 or 4.08 They all have little tricks to compensate for the extra sidewall stress, like piston material, piston shape, rings, etc, etc, etc,. I heard a lot, but still decided to go with the 3.795 for my first stroker.

I'm getting ready to do another stroker now for my Challenger and am going to probably go with the 4.0 or POSSIBLY the 4.05 I don't think there'll be a problem. I think the best advice for the OP will be keeping under a 4" stroke; minimal bore increase; correct pistons, etc.
 
The 6.1 has 4 bolt mains and cross bolted to the block as well equaling The 6 bolts per main. The 5.7 only has 4 bolts per main 2 main fasteners and 2 cross bolted. That is the extra beef it allows a wider saddle area which makes more saddle structural integrity due to its extra width. The 5.7 is built well enough extra saddle material like the 6.1 is mostly irrelevant to a point these blocka wont reach anyways.

The 5.7 block is nearly identical to the original production gen2 hemis with better saddle seat sizing. We know what those made power wise. The newer tech casting is much better structually then back in the day to boot.

Either will get the job done but boosted the 5.7 cylinders are thicker but it is "my" preference. Id like the bigger bore myself but I wont sacrifice integrity for size. Cost wise stsrting from scratch is a huge cost difference to boot.

There is a jeep out there that broke a few 6.1 blocks before going to the 5.7 and went faster with it and still together for quite a long time comparably.

N/a will never see cylinder pressures of a boosted application.
 
6.1 has 4 bolt mains just like the 5.7. Aluminum 6.1 blocks have 6 bolt mains. LS's have 6 bolt mains to.
 
I guess thats what I get for looking at those two and not the cast 6.1 block. Lol

I still stand by my words that there is no significant difference of the two saddles in the main area. Anything would be negligible anyways as the cylinders are the weakest link in the blocks.
 
Oil squirters can be a real advantage in a boosted engine. In the final years of the air cooled 911s oil cooling provided nearly 40% of the total cooling for the engine. Clearly the water cooled hemi doesn't require this level of oil cooling but the spraying the undersides of the pistons with oil would reduce the chance of detonation which is particularly important boosted applications.

I wonder if you could drill and tap the 5.7 block for squirters, and if it would be worth the effort.

Regards,

Joe Dokes
 
Joe Dokes said:
Oil squirters can be a real advantage in a boosted engine. In the final years of the air cooled 911s oil cooling provided nearly 40% of the total cooling for the engine. Clearly the water cooled hemi doesn't require this level of oil cooling but the spraying the undersides of the pistons with oil would reduce the chance of detonation which is particularly important boosted applications.

I wonder if you could drill and tap the 5.7 block for squirters, and if it would be worth the effort.

Regards,

Joe Dokes
Click to expand...

Is the oil valley there in the center for them? Would be simple if so.
 
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