Slant 6 vs. 340 vs. 3G Hemi

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RTom

RTom

Depressingly A-Bodyless..
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So, I've got a 69 Dodge Dart GT Convertible that currently has a plane jane slant six in it. I know that I do not want to leave it how it is, but as to what I want to do with it, I'm not exactly sure. I'm tossing around three different plans right now, and would like to get your opinions on them ( I will list the pros and cons I see, and if you guys see any I am missing, please chime in :cheers: )

Turbo Slant 6:
I've been reading up a lot on turboing the slant six. I have found that it can be done relatively cheaply (less than a grand). A turbod slant six can be making in the neigherborhood of 400 HP and still get 30 + mpg ( if you can keep your foot out of it ). I like this idea because I can combine both the fuel economy with performance (and being able to do all of it with a slant six)

69 340:
I've got a 69 340 block that I have thought about stroking. I know with a properly built stroker 340 450 + HP is easily attainible. However, I know it will cost me at least 2-3 k and fuel economy will be a joke. I like the idea of saying I have the 340 in it, but don't know if it is worth the extra money.

5.7 Hemi Conversion:
I've wanted to put a new hemi in my Dart for a long time know. With how many people are doing it, it seems to have gotten to be relatively straight forward (relatively). I like the performance and fuel economy that you can get with them. I also like the idea of having a 'new' engine in an old school car. However, this is not cheap by any stretch of the imagination.

Right now I am a ways away from doing any thing with the engine. I would just like to start planning now so I can slowly stock pile the needed parts. My end goal is to have my Dart be a daily (summer) driver that will be reliable and still have some good old power. I'd love to hear what you guys think!
 
Bang for the buck even a mild 340 would be my choice. then you can say you are running the best small block ever made!8)
 
I put my vote in for the 340. The hemi would be great but a lot of work, the slant six will require more money than it's worth to be powerful, and the 340 just feels right, not to mention they're easy to make power for.
 
Last year at a cruise in, there were two cars I could not stop looking at, well under the hood anyway. A 71 Duster with a 5.7 Hemi and a 67 Valiant with a turbo /6. Either way there is going to be some fabrication, brake upgrades, etc. But with the /6 you will not have to upgrade to V8 suspension. I vote turbo /6.
 
You would be hard pressed to get 30 mpg out of any slant 6 let alone one that is turbo charged so I don't think you will see any huge mileage advantage over the 340 and will likely get less than a new hemi. Also a 400 HP \6 is going to require internal mods and head work to get to that HP level and that isn't going to be cheap. I think you will find it's going to cost you as much to build the \6 as to build the 340.

My recomendation would be to sell the 340 to some one doing a restoration and pick up a 360. The money you can make will go a long way toward paying for the 360 build.
 
Since you have both the slant and a 340, you've got a couple of good choices. Upgrade the slant enough to take advantage of a set of triple Webers or triple SUs; you will have the "WOW" factor and will run pretty decent as well. and not break the bank (too much). For the 340, well it's a 340 and everyone knows how they run.
 
My vote (only because this is what I plan on doing) would be to sell the 340 AND the /6+transmission and buy a running 360 vehicle. If you swap in a v8 you'll need a tranny, bellhousing, etc. If you buy a running bigger car or small truck, you have all the little extras, or at least most of them. I have owned a /6 dart and a 360 ramcharger, the /6 wasn't too bad, but the 360 really hauled that heavy truck around!
 
Turbo /6 You will have a TON of customizing and fabrication on your hands. You'll also need to upgrade brakes, transmission, rearend, etc. if you make serious power. Even if you don't go turbo, a /6 will be hard pressed to make 30 mpg.

340 You'll need a v8 k-member or conversion mounts, a v8 tranny, new driveshaft, stronger rearend, better brakes, etc. BIG $$$ beyond the actual motor, and crappy gas mileage.

3G Hemi All of the above, plus major wiring headaches. I still haven't seen anyone making plug and play conversion kits for this.

I agree with 65 Dartman. Just upgrade the /6 with Clifford intake and Dutra dual exhaust and call it a day.
 
dgc333 said:
You would be hard pressed to get 30 mpg out of any slant 6 let alone one that is turbo charged so I don't think you will see any huge mileage advantage over the 340 and will likely get less than a new hemi. Also a 400 HP \6 is going to require internal mods and head work to get to that HP level and that isn't going to be cheap. I think you will find it's going to cost you as much to build the \6 as to build the 340.

My recomendation would be to sell the 340 to some one doing a restoration and pick up a 360. The money you can make will go a long way toward paying for the 360 build.
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Ding-Ding;Ding!! Winner!!
Leave the 340's for the resto crowd and get a 360!!
 
340 best $ per HP you can build, add a stroke crank=monster bolts in stock!
 
GoFish said:
Turbo /6 You will have a TON of customizing and fabrication on your hands. You'll also need to upgrade brakes, transmission, rearend, etc. if you make serious power. Even if you don't go turbo, a /6 will be hard pressed to make 30 mpg.

340 You'll need a v8 k-member or conversion mounts, a v8 tranny, new driveshaft, stronger rearend, better brakes, etc. BIG $$$ beyond the actual motor, and crappy gas mileage.

3G Hemi All of the above, plus major wiring headaches. I still haven't seen anyone making plug and play conversion kits for this.

I agree with 65 Dartman. Just upgrade the /6 with Clifford intake and Dutra dual exhaust and call it a day.
Click to expand...


Check around, at least 4 places make plug and play type 5.7 and 6.1 harnesses. It's getting alot easier, not cheaper however to swap in a 3g Hemi.

Riddler
 
69_Dart_GT_Conv said:
So, I've got a 69 Dodge Dart GT Convertible that currently has a plane jane slant six in it. I know that I do not want to leave it how it is, but as to what I want to do with it, I'm not exactly sure. I'm tossing around three different plans right now, and would like to get your opinions on them ( I will list the pros and cons I see, and if you guys see any I am missing, please chime in :cheers: )

Turbo Slant 6:
I've been reading up a lot on turboing the slant six. I have found that it can be done relatively cheaply (less than a grand). A turbod slant six can be making in the neigherborhood of 400 HP and still get 30 + mpg ( if you can keep your foot out of it ). I like this idea because I can combine both the fuel economy with performance (and being able to do all of it with a slant six)


400 hp for under a grand? and 30 mpg? i really doubt that.



69 340:
I've got a 69 340 block that I have thought about stroking. I know with a properly built stroker 340 450 + HP is easily attainible. However, I know it will cost me at least 2-3 k and fuel economy will be a joke. I like the idea of saying I have the 340 in it, but don't know if it is worth the extra money.

if i went small block i would go 360. sell the 340 for a profit to a resto guy. the 360 tq is so nice on the street. anything they make for a 340 can be bought for a 360 now and your starting with 20 extra cubes....

5.7 Hemi Conversion:
I've wanted to put a new hemi in my Dart for a long time know. With how many people are doing it, it seems to have gotten to be relatively straight forward (relatively). I like the performance and fuel economy that you can get with them. I also like the idea of having a 'new' engine in an old school car. However, this is not cheap by any stretch of the imagination.

that would have thew best of all worlds. starting from scratch i'll bet its not all that much more then putting a small block in the car. fuel system and computer system are the biggest expense difference. but if starting with a low mileage motor out of a wreck compared to rebuilding a motor put it closer then you may think.

Right now I am a ways away from doing any thing with the engine. I would just like to start planning now so I can slowly stock pile the needed parts. My end goal is to have my Dart be a daily (summer) driver that will be reliable and still have some good old power. I'd love to hear what you guys think!
Click to expand...


the main thing is what do you want from the car when its done? drag car, cruiser?

with any of the choices and even keeping the stock slanty in it i would still convert to big bolt disc brakes up front and larg bolt in the rear...
 
Riddler said:
Check around, at least 4 places make plug and play type 5.7 and 6.1 harnesses. It's getting alot easier, not cheaper however to swap in a 3g Hemi.

Riddler
Click to expand...


saw a guy at atco with a coronet and a 5.7 in it. tti headers and conversion mounts and street performance computer harness. thing was into the 13's with a stock motor and hardly any traction and crappy gears. impressive man..
 
i say do a 360 to 408 stroker....forged bottom end, eddy or RHS heads, hydraulic roller cam, hughes 1.6 roller rockers..tti headers...you will have alot of fun! of course, with any build it is necessary to build the suspension and drivetrain to handle it.. :)
 
Put a new 6.1 hemi in it. Then you can one up all those 5.7 guys. haha.


Honestly, of what you have said and what you'd like to do, I say go with the slant 6. I love turbo mopars of all sorts though so I may be biased, but you must admit it would be a cool and DIFFERENT setup at the local cruises. Different is a big thing for me. (this is coming from the kid who's going to run twin weber sidedrafts in my rampage)
 
I'am doing up a 71 dart and going with the 6.1 hemi stroked and blown. more work but will be sweet when done. motors are easily found at a wrecker seeing as there in everything now and there is lots of stuff out there to do the conversion. i know people who have got 5.7L for $1500.00. it all depends what you want. i want a modern muscle car so 6.1L a modern hemi Dart. the 340 would be nice to. good luck and keep us up to date.
 
Thanks for your input so far.

I have already upgraded to large bolt patter disc brakes up front and large bolt pattern drums in back. Regardless of what engine I go with, I will be putting in a posi 8.25 or 8.75.

Even though it would be cheaper to go with a 360, I'd really prefer to say I have a 340 under the hood ( if I go that route ). I really want to make this Dart a one off, unique rag top. I feel a 360 is just to common. I'd like to be able to drive this on the cruises and pop the hood and have people surprised. While the 340 would be sweet, I think the turbo'd slant 6 or 3G hemi would really be much cooler.

Regardless of what I do, I will be making a thread dedicated to my Dart with in the next couple of weeks.

Thanks guys!
 
djwhog said:
340 best $ per HP you can build, add a stroke crank=monster bolts in stock!
Click to expand...

Actually the 360 is a better $ per HP prospect.

You are starting with more displacement so you have a potential power advantage there. If you are shopping for a block there is a huge price difference between 340 and 360. Even if you have a 340 block you can sell it, buy a 360 and have several hundred dollars left over to fund the rest of the build. Pistons are significantly cheaper for a 360 and there are more choices for the 360. Everything else is going to cost the same. Also, the 360 piston is much lighter than a 340 piston negating any supposed rev advantage of the 340.

If you are talking about a stoker kit the kits in the 360 sized mains are less expensive and the few cubes more you get starting with the larger 340 bore is insignificant in the power producing capability.
 
340 or 3G, with the 340 being cool old school, and the 3G being cool new school + gas mileage.
 
The stock 360 is the best bang for the buck

But when stroking the 340 block has bigger bore so the 340 block will have more cubic inches

360 stroker is 408
340 stroker is 416
of course the cubic inches will vary based on the actual bore but you get the ideal.
 
I would be interested in how cheap and how much real world power you could get out of a turbo 6. That would be neat to follow. I vote for the turbo 6

You would not be disappointed with any stroker small block build even a budget build.

The new Hemi would be cool but doesn't fit my muscle car thinking of lopey idle. But if you are going to include a pro touring suspension, big brakes, 17" wheels and air conditioning I say it would be a perfect match and a lot of money.
 
i was in this exact position. i started with a super six 2 brl and a 2.5" exhaust on my slanty. i had a turbo buick co-worker in search of some turbo stuff for me, i was driving the car a lot and i felt i had it runnign very well and could not beat 18 mpg. 14-16 was common. i started thinking if i wanted to make power it really would be foolish to start with a 225. yeah its possible but there are more effective ways to make power. i sold off a car and put some good money in my pocket and i promisied if it sold i was going with a 5.7 hemi and t56 in the duster. i read and re read every thread and site i could find. stuff starts to get real expensive. 345hp for how much $$$ involved? yeah the efi would be nice, but nice but would it offset the investment? i then looked at the 400,
727, k frame, headers, a few different intakes, pile of bb heads, and i decided it it was foolish to go with anything but a bb. i figure with a set of stealth heads i can get the wieght down, and it would be pretty easy to make the same power as the 5.7 hemi. i decided ill never make power and get good mpg with the 727 so im picked up a t56. i honed, new rings, bearings, cam lifters. short block is back together. im not looking for big power with this car but enough low end torque to lug it along in 6th on the highway at low rpm. gonna try a thermoquad. i havent decided yet if im actually going to go with a set of stealth heads or just pocket ported 452s. hopefully ill start the swap in the next few months.
 
If you want something really unique, go with the turbo slant. Plus you can really make people shake their heads when you dust them off and they ask what you are running.

The problem with the slant is you will never get any respect, even if you can run 11's. So don't build one if you want more than the curtsey "nice car" when you catch someone looking at it.
 
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