Need to make a decision fast 5.7/6.1/340

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MoparOrNokar

HammerTime
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Flint, Michigan
This spring i bought a 70 duster with a tired mild 360. Now after a summer of my foot on the pedal she is real tired. Im debating on throwing a 5.7 hemi in for performance and economy. I want a street/strip car but i also dont want to pass everything but a gas station.

The guy i bought the car off wants to sell me a 340 with 9.5 pistons, steel crank, with headers and he has a set of edlebrock heads that need to be machined. He wants $4000 for the setup but the way i look at it is thats $4k for a used motor. He claims around 3k miles on the build. I also want more horse than what he claims in that motor. Im shooting for 450hp

Im womdering if someone who has done the 5.7 swap can tell me any pointers they have with problems they ran into and a round about price to do the swap. Im not looking to change the K member or anything makor like that. I PLAN ON putting my. 727 behind the 5.7
 
for 4k you could build new motor unless your a good at fab work I would stay away form the 5.7 or 6.1 my vote would be a 416 but they are not cheap I have 10k in mine.
 
Winter's coming...I just bought a 2013 5.7 (non MDS) with 3000kms for $1600. Figure by the time the dust has settled I should be turnkey for about 5 grand. That's TTI headers and conversion mounts, Milodon conversion pan, Holley HP ECU and harnesses, aftermarket fuel pump, etc. This engine is 395 stock. When one considers the difference in mileage between a 400 horse LA or B/RB against a Gen III Hemi, even if it costs you a bit more in the short run, it's going to pay you in spades in the long run!

My .02 for what it's worth...
 
for $4k, I would just buy a 6.1 hemi and be done with it. You would not be disappointed.
 
You also have to remember the newer hemi is also made for today's synthetic oils, smooth valve train, 50 / 80 lbs lighter and breathes WAY better than an old LA motor. Don't get me wrong, I have both but prefer the new Hemi. Just wish the prices of the 6.1 would drop, 5.7's can be had for under a grand.
:burnout:
 
I have been a fabricator/welder for about 12 years now so that part doesnt intimidate me. I just dont want to start this project and end up with 15k into just having the motor in. I guess i just dont understand all the parts that im going to need. Its the electronic part that i dont understand and the fuel system. Someone said to look at the fast efi 2.0 but thats $3k right there. Idk what to do. I want my car drivable again by spring. Living in michigan, that gives me about 6 months lol
 
I did the swap around 3 years ago and pretty much had it back on the road for $5k (engine included), but that was with a carb. I didn't have the money to upgrade the fuel system to high pressure the way I wanted to for EFI at the time. I've since switched over when I got a deal on a Megasquirt setup, but if you get all the stock stuff with the engine you could probably still keep costs down. I didn't get any harnesses or computer with my engine or I might have considered that route from the beginning. I know a guy near me with a 74 Cude that did the swap that has more in his engine bay than I have in my whole car, but that's just the way he wanted to do it. You can always start cheap and work up replacing parts one at a time. That's more or less how I planned my build. Never wanted the car off the road more than a week or so at a time, so I did a basic swap to start and can replace parts with prettier ones as I feel the need.
 
Jeep 5.7 Hemi manifolds - used $200
Hotwire Auto wiring - $900 with a 727 trans
Hotwire Auto used computer - programmed $300
Mancini Racing motor mounts - $150 or build own which you will probably do
Get a Diablosport Intune for any computer tune modifications for when you modify the engine
Plus the price of buying a Hemi
 
What needs to be done to the fuel system to run the efi? My plan is to put in stock (maybe a cam) at first then build up. When you buy a megasquirt or holley hp does that replace the stock harness and computer or do i still need the stock harness and computer. I guess im basically looking for a complete parts list that i will need to complete the swap. Thanks for all your input guys
 
I also dont understand the options when it comes to the throttle. I would like keep the cable if possible. And i heard you can use a durango oil filter bracket because its at a 45 degree angle. Is this true or is it better to go remote
 
jrlegacy23 said:
Jeep 5.7 Hemi manifolds - used $200
Click to expand...

You mean these: 2003-2008 5.7 jeep manifolds ???
Will any other stock manifolds work for this a body swap?

If so, here is a set on fleabay ($100 - not mine):
[ame="http://www.ebay.com/itm/Exhaust-Manifolds-5-7-Hemi-Grand-Cherokee-2005-2008-/291222270389?pt=Motors_Car_Truck_Parts_Accessories&hash=item43ce3331b5&vxp=mtr"]Exhaust Manifolds 5 7 Hemi Grand Cherokee 2005 2008 | eBay[/ame]
 
You can either modify a fuel sending unit to put in an aftermarket fuel pump and sending unit, or you can go the cheaper route like I am doing. I bought a MSD external fuel pump for a Corvette for $169. It comes with a Corvette fuel filter that has a built in regulator, which happens to be the same PSI as the Hemi requires. Here is a link to it:
http://www.speedwaymotors.com/LS1-Complete-Fuel-Delivery-Kit,41792.html
 
d100clubcab said:
You mean these: 2003-2008 5.7 jeep manifolds ???
Will any other stock manifolds work for this a body swap?

If so, here is a set on fleabay ($100 - not mine):
http://www.ebay.com/itm/Exhaust-Man...Parts_Accessories&hash=item43ce3331b5&vxp=mtr
Click to expand...

No, not those. The ones that look like headers. These:
[ame="http://www.ebay.com/itm/Jeep-Grand-Cherokee-SRT8-Headers-Exhaust-Manifolds-2012-2014-/281439247818?pt=Motors_Car_Truck_Parts_Accessories&hash=item4187161dca&vxp=mtr"]Jeep Grand Cherokee SRT8 Headers Exhaust Manifolds 2012 2014 | eBay[/ame]



images
 
The 340 is over priced. Easier to build another la motor for it because you have all the accessories already.

The Hemi is cool too. You have to add up what the fuel system will cost to do the right way and the computer stuff.

In my opinion if you aren't going to use the efi the. Just go la motor.

I would also do what I had to and go with an od trans. Either an a500 or one that requires more cutting. Without od I don't see the Hemi getting all that much more mpg.
 
abodyjoe said:
The 340 is over priced. Easier to build another la motor for it because you have all the accessories already.

The Hemi is cool too. You have to add up what the fuel system will cost to do the right way and the computer stuff.

In my opinion if you aren't going to use the efi the. Just go la motor.

I would also do what I had to and go with an od trans. Either an a500 or one that requires more cutting. Without od I don't see the Hemi getting all that much more mpg.
Click to expand...


Im really going for reliability and i like the tunability. Im running a 3.91 gear now with the 360 so milage really isnt important lol
 
well if mileage isn't important then you can go with either motor.

both the la and hemi can be very reliable so thats a wash.

both can be tuned so thats a wash

both can be done to run with a carb or efi so thats a wash..

both can make reliable power so thats a wash..


its personal preference man.. but the decision will be made from some factor you have in mind. it could be so you can say you have a hemi, could be because you have all the bolt ons for the la already. these are things no one can answer but you.
 
I recently went through this. I ended up going with the 340 with reliability, power, and budget in mind (i planned on "daily"ing it). budget was the first thing destroyed. i ended up 11k into it. in hind sight if i knew then what i know now i would have gone 6.1 and never looked back. reliabilty power and mileage to boot. they really are great motors
 
my question is will a non OD hemi get that much better mileage than a non OD LA motor? just curious. i don't know the answer. i know the efi can make it more efficient because its constantly fine tuning but efi can easily be put on a LA motor.
 
Why not go to the 6sp behind a Hemi. Toss on a supercharger and have something that is totally bad
 
The Hemi has more potential in the long run (in my opinion at least), which is one of the main reasons I went with one over an older style engine. I was debating a small block stroker build, a supercharged junkyard Magnum build, an aluminum big block build, and a modern hemi swap and they all had similar starting prices. You had to build the smallblocks up quite a bit though and they became pretty high strung to get the same kind of power a modern Hemi could get with far less parts. My mileage has slowly creeped up as I've worked on the tune and other stuff, but in reality I'm still pushing a brick through the air so I can't expect too much. The mileage hasn't changed much from the 16mpg I was getting with the junkyard 318 that was in the car when I bought it, but I have probably doubled the horsepower and still get 16-18 mpg. Might be closing in on the magic 20 I've been aiming for with some better tuning.
 
option 3. rebuild a 360 roller and put MP-EFI on it. Bung a Victor Jr. Intake and MS it or go real cheap and get a chevy MPFI ecu/harness/sensors and re-flash it. Peanuts compared to Edelbrocks Pro-flo2 at $3500.
good: same trans, same motor mounts, same everything! GM EFI parts are cheap and everywhere
cons: need electric fuel pump, and means to reprogram ECU (tuner shop), using a GM brain for a Mopar heart.......sob.
 
Map63Vette said:
The Hemi has more potential in the long run (in my opinion at least), which is one of the main reasons I went with one over an older style engine. I was debating a small block stroker build, a supercharged junkyard Magnum build, an aluminum big block build, and a modern hemi swap and they all had similar starting prices. You had to build the smallblocks up quite a bit though and they became pretty high strung to get the same kind of power a modern Hemi could get with far less parts. My mileage has slowly creeped up as I've worked on the tune and other stuff, but in reality I'm still pushing a brick through the air so I can't expect too much. The mileage hasn't changed much from the 16mpg I was getting with the junkyard 318 that was in the car when I bought it, but I have probably doubled the horsepower and still get 16-18 mpg. Might be closing in on the magic 20 I've been aiming for with some better tuning.
Click to expand...

more potential? guess that all depends what you want in the end...

i'm not saying either is better but i have a friend with a real mild 360. stock bore and stroke and a 3.23 gear and FAST EZ EFI thing dips in the 12's and gets about 17mpg. between the motor and efi i bet he maybe has 5k into it. only thing in the bottom end thats not stock is the kb 107's. it even has stock rebuilt smog heads on it. i'll bet he hasn't checked the mpg with the new headers and exhaust either. it was really choked up before now its a ton more free flowing so i would think et and mpg have improved. i'd like to see what an OD trans would do for the car too..

whats a abody with a 3.23 gear and a modern hemi run in the quarter? i know of a coronet with a 5.7 and 3.23 and it was dipping into the mid -high 13's so a stock 5.7 is no slouch either...

someone should do an article on the pluses and minuses of both with ballpark dollars it takes to do them..


i know if i were doing a modern hemi swap all i'd want is a stock 57 or 6.1 running a stock computer with all the efi and an od of some sorts in it... i don't need to be going crazy with all kinds of mods because it would be more a cruiser then anything else..
 
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