340 or 383 for 1968 Dart

[barbee6043]

Unless it's an original 340 car, big block EVERY TIME. We've done 383 and 440 swaps and have an original 340 car. The 340 is fun, but it doesn't have the torque of the big block.

Yes, torque, that is the difference!!! For sure.
Want more umph? Do the 400 stroker thing.

 

[barbee6043]

I'm surprised there aren't more 360 guys chiming in.

They are all still busy pulling out th e slant!

 

[oldkimmer]

I recently bought a 383 (69 335 HP) 727 auto swapped 68 Valiant so you know where I stand. It already had the Shumacher shorty Tri-Y headers on it easy plug access. I have an aluminum intake, water pump and housing awaiting paint and installation sitting on the floor in the living room. Battery is already in the trunk. I chose the big block because I had never owned a big block before, I was looking for that low end torque. My current dilemma is whether to change out the lumpy cam in the car with a high lift short duration cam that would match the gearing or change the 2.9 rear end for something that matches the existing cam. Fear of bad lifters is a factor.

My dart cruises ok with the 383 and 727 with the factory high stall converter and 3.23 gears. There’s a Comp cam 292/501 cam in it. Ported and polished 906 heads with bigger valves, Torker intake and 650 double pumper. Kim

 

[340six]

They are all still busy pulling out th e slant!

I thought they were fighting over if the 360 truck engine was as good as a 340 4bbl.

 

[nutz]

Man o man. Lots of bs on here.

Real 340 car gets a 340

Even my not real 340 car gets a 340
And I have found every part on fb within 2hr drive

 

[Derrick Kidwell]

I have a question I don't know the answer to:
How much more does a 400 with aluminum heads weigh, that an iron head 340?

The comparisons I've seen if you also go aluminum water pump and water pump housing is only about 15lbs and you have a front position distributor, external oil pump with easy accessible oil filter and the dry intake manifold no mess of antifreeze when you work on it. All that 340 is a mean machine and roomy engine bay. Either way has some benefits.

 

[360notch]

What would be your preference and why?

I've had both with 4 speeds, and both were great. Just emotionally, the 340 was more fun to drive. The 383 had a lot of torque. Car seemed more balanced with the 340. 340 seemed to rev quicker.

 

[Cranky]

They are all still busy pulling out th e slant!

 

[barbee6043]

Over size front sway bar takes care of the nose heavy with the BB. Had such in '67 383 Barracuda. It would pretty much fly around curves.
Heck, a front engine dist. is enough reason alone for me!

 

[33IMP]

i know, but the gen 3 hemi and 440 guys chimed in. As i said they made less than 15,000 in total so to
alter one a lot might not be a good idea... i wouldn't. Still a guy can do whatever he wants to his car...
I thought the 383 option would be preferred because it is so rare?

Imo, a non-stock 383 swap into a real 340 car is a step down.
If it was a REAL 383 car, then 100% put a 383 in it!
For me personally, I often prefer a non-collector-grade Mopar, so I can do whatever I want to it.

 

[matthon]

 

[Bennoel 10]

View attachment 1716471164

Looks like an EMD 2 stroke, turbo charged, V16 locomotive diesel ? I think it might just work. Lol.

 

[66fs]

Just got home guys...lots of super responses! I screwed up and should have mentioned the gentleman actually has a 68 340 GTS, but the original 340 is gone. He has a 383 with the correct 383 K frame, motor mounts, exhaust manifolds and rebuilt big block rad! Also has a '70 340 with hi flow manifolds and correct rebuilt 340 rad.
A tough decision for sure. I think the 383 with the correct pieces may edge out the 340?

All the correct 383 parts you mentioned are worth a lot of money and are very rare. Is there a price difference between the 2 set-ups? The 340 would be the easiest, but I do love my 383 car and it is an automatic. It was a daily driver for years. I have had both engines in an A-Body, and I would pick the 383. I have to laugh when people say a 383 is a dog. It was a highly factored engine in NHRA stock class. The heads and cam are the same as a HP 440, so if I swap the HP 440 AVS onto the 383 what is the difference in horsepower? Not much. I knew a lot of 383 roadrunners that could beat 440's. As for handling and braking, they were plenty good, no need to reinvent the wheel for little or no gain. My factory 383 car came with .89 torsion bars and a .94 front sway bar. The only thing I swapped were 10 in drums for K-H front discs and the 14 x 5.5 wheels for 15 x 7 Rallyes.

 

[chilsam]

put a inverted V16 HEMI in it !

 

[ir3333]

383 dog...not so fast. A lot of them were very low compression with tall decks, pistons that sat way down in the bores and the large 90 cc chambered 906 heads. Built properly they could be very fast...especially in a light A body!

 

[mayhem]

I'm afraid I can't help the OP with his decision as I sold a bunch of 340 stuff for a different kind of big block...

 

[RustyRatRod]

Imo, a non-stock 383 swap into a real 340 car is a step down.
If it was a REAL 383 car, then 100% put a 383 in it!
For me personally, I often prefer a non-collector-grade Mopar, so I can do whatever I want to it.

I'll go along with that. Even if it's a non matching 340 into a real 340 car.

 

[RustyRatRod]

I'm afraid I can't help the OP with his decision as I sold a bunch of 340 stuff for a different kind of big block...

View attachment 1716472215

lol

 

[ir3333]

So many advantages when building a regular dart, satellite or duster...but if possible i still prefer to have a real roadrunner, GTS or 340 duster...

 

[barbee6043]

So many advantages when building a regular dart, satellite or duster...but if possible i still prefer to have a real roadrunner, GTS or 340 duster...

All about what you find and what it costs!!
Last time I saw a only 80% rusted out 68-70 RR projects was what??? 1999????? and it was also silly high $$$ !!!

 

[Jim Lusk]

I have owned both a 383 and 340 FS FB. The 383 was stock so heavy. Putting 0.94" torsion bars and a 1 1/4" sway bar really changed the handling. Yes, a 383 with AL heads and other low weight parts weighs about what a stock 340 weighs, but a 340 with AL heads, intake and tubular exhaust is nearly the weight of a /6. I actually enjoyed the 383 a lot as it was a 4sp while the 340 was a 727. But the 340 was much faster as the 383 was the 290 HP version. I did update the cam and ported the heads along with unshrouding the intake valve to cylinder wall, but the 383 still wasn't as snappy as the 340.

Unfortunately, I had to sell the 383 and have no idea where it ended up. The next owner sold it to a third-party weeks after buying it.

I can attest to the handling of that car. That one ride in it was enough to convince me...and that was a LONG time ago...

 

[matthon]

If it was a REAL 383 car, then 100% put a 383 in it!
For me personally, I often prefer a non-collector-grade Mopar, so I can do whatever I want to it.

I have a real 383 car, don't consider it collector grade, I mean, it's an a-body, right?

I do whatever I want with it, fully enjoying it.

 

[nutz]

If it run it fun ...

 

[oldkimmer]

My car is not a real 383 car. It was born a dart 270 with a slant. LH23B8B. I first put a 70 340 into it. Drove it about 7 years. Then it was 383 time cause I bought a thrashed 68 Coronet with 383/727 3.23 suregrip. Rebuilt everything and installed it into the dart. Drove it about 5 years then sold it in 1995. Got it back in 2025. Kim