Turbocharged 340 Mopar

[Turbo231]

I have just bought an old Plymouth Duster and want to build a turbocharged 340 engine to go in it for drag racing. I haven't played with Mopars in years and quickly found out that 340 parts are tough to find now. I want to use the 340 for its shorter stroke and higher revving capability, vs. the later 360's. But I have a budget and don't want to pay a premium for rare engine parts. Looking for suggestions here from any Mopar guys out there. I am wanting to get 600+hp and run 6500 rpm. Plan twin turbos with air/air intercooler.

[cv67]

Scat doesnt make anything?

[PackardV8]

turbocharged 340 engine to go in it for drag racing. . I want to use the 340 for its shorter stroke and higher revving capability,

There are some who would say that's beginning at cross purposes. What turbos do well is make power at lower RPMs.

Unless one is aiming at a specific displacement class, there's both a performance penalty and a cost penalty in building a 340" versus a 360" or 400".

As an aside, we never saw coming the recent popularity of the 400". We're sitting on a dozen 440" cores which were in demand then, but not today.

[CamKing]

For a 6,500rpm max, I would go with the 360. The added displacement, and stroke, will get the engine up on boost quicker.
With 9.5:1 compression, you can make 650hp with less then 8 lbs of boost, and a hydr cam in the 224@.050" range.

[Krooser]

You can get to 600 HP N/A without much trouble.

I think a stock forged Mopar crank with the stock stroke will be strong enough... They bring $100- 150 on the used market. Scat and Molnar have decent import forgings .. I have an old Mopar Performance 3.79 stroke billet deal for my SBM dirt motor.

Heads are where the HP is at ..used W2's are fairly plentiful and the new Edelbrock Victor heads are very good. Trick Flow will have a new head available soon... Good flow but not as good as a Victor

Brodix also has a few heads for the SBM...
...

[user-23911]

Just keep it stock. Add boost, add water injection, fix what breaks.

[paulzig]

Buy a 318 or a 360 instead of the 340 which are getting harder to come by..

[quickd100]

I made 536hp with a stockish 318. 318 uses the same crank as a 340, same rods just uses a smaller bore. 318s are cheap and plentyful. O-ring the deck, use Clark copper head gaskets. A 318 can make enough hp to scare you.

[F-BIRD'88]

I'd do the 318 motor too.
Torqstorm blower, water/Methanol injection.
Keep it simple.

[Jeff Lee]

My 1st ever build was 340. Love that engine! But I do remember a ’72 ‘Cuda I bought that had a 318 with 360 heads and something slightly better than an RV cam. With headers, a Thermoquad on a cast iron intake, TF & 3.55 gears, that was an amazing car. And you can probably get a 318 for next to nothing and you’ll have meatier cylinder walls which is what you want with a boosted engine along with the forged 318 crank. Spend the money on aftermarket heads and the turbo. It should be a plenty good ride on the cheap. If you want to spend money then you go Scat 400+” stroker 360.
Personally, for what your after, I wouldn’t do it to a 340.

[Justin_inc]

I'm sketchy on the older mopar blocks, make sure you get the wall thickness checked for sure if not do a 1/2 fill on them. We split two 360 blocks, one on 13psi with twin 78/75 turbos, and the other at 8psi. Never dyno'd the car but always had extremely conservative tuneups, went 6.29 to the 1/8th at 6psi in a 73 Road Runner with 18* of timing trying to creep up on the tune.

[F-BIRD'88]

Of you really want a good motor to super/turbo charge and rev up, for your Duster, get a 383 BBM It will do everything the SBM motor will but BETTER!

[mag2555]

I gotta say I don't see any logic in going with a duel Turbo set up to make under 700 hp with only 340 cubes to feed!
I see at as just adding more complexity and certainly not making things any cheaper!

[ptuomov]

I gotta say I don't see any logic in going with a duel Turbo set up to make under 700 hp with only 340 cubes to feed!
I see at as just adding more complexity and certainly not making things any cheaper!

If it’s a street car, twin turbo setup is a lot better than a big single. Plus the difficulty of making durable manifolding for a big single negates any cost advantage. Has any car factory ever done a big single turbo V8 in a gasoline powered passenger car? Can’t think of single make or model.

[user-23911]

I've done it...years ago, twice, same turbo on 2 different engines, only because I couldn't get nor afford a second one..........too much time spent every weekend fixing leaks.
Single turbo on V8, just not worth the hassles.
Welds always crack when you use the wrong materials, on top of that, you reinforce the welds, the header plates warp and leak.It's a loosing battle.

Ideally you want to make use of the factory cast iron manifolds and make adaptors to the turbos.