71 cuda - 340 lost, what`s the best replacement?

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I recently bought 71 cuda, originally 340 (unfortunattely lost 20+ years ago), not running since. It is 4 speed car, transmission still there. Because of 340 engines are expensive (12k for crate engine), I`m considering to use 408 stroker (360) engine instead, which are around 7k, and they shoudl have more HP. It is my first E-body, have no experience, so here are my questions?
1. will 360 (408) fit without any frame adjustments or adapters to 340 car?
2. will it fit to original 4 speed?
3. any recommendation, where to buy 408 (engine builders, etc...- I found it on Summit and Ebay from ATK)
4. in general, is it smart to use this type of engine? Or would you recommed something totally different?

The reason why I want to keep it small block is because of weight and easy handling.

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If you want to find an inexpensive engine, I would go with a 360 magnum from a truck/dakota. If you have a decent budget, I would go with Gen 3 Hemi and transmission. If you can buy a wreck in your country to transplant everything, that would save you quite a bit of money. A Gen 3 hemi will get you quite a bit of power for the buck plus mileage.

Welcome to the board. Please start a post with your build and post lots of pictures!

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"best" is subjective and depends on your needs/wants/useage and how close to stock you intend the car to be.

I have zero interest in having a modern hemi in a classic car, so "best" for me would be a 340, followed closely by a 360 (likely stroked).


Dave

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You might have a balance problem with the 360. They are externally balanced. You need to know if your current flywheel is for an internal or external balanced engine. If internal. Then use a 318 block and a 4" stroke crank. But on second thought. It might require either combo to be internally balanced.

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another 340 is the answer...hell of a better motor than a 360

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If built the same,part for part, the 360 would be the stronger of the two right? Unless the larger bore size of the 340 would make a huge difference.

And when both get a 4" crank then you'd have a 408 and a 416 that should run pretty evenly. If thats true then the 360 woukd look better to me simply because of the lower initial purchase price.

Add in the ability to go magnum based stroker with the better heads and roller cam (no worry of wiped lobes), then I'd really lean 360.

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The 340 and 360 are the same engine on the outside.

The original 4-speed will mate to the 360, they were available that way when new. The bellhousing (part that goes between the engine and the transmission) is the same for both.

Make sure that you get a flywheel that matches the engine. By that I mean the flywheel will have 130 tooth ring gear, and have the normal MOPAR 6-bolt flange. But 340s and 360s had different balance. And who knows how a stroker is balanced. So, you need to make sure that WHATEVER engine you buy has a harmonic damper and a flywheel that are balanced to the particular engine you are getting.

For a clutch the flywheel will have a 10.5" pressure plate bolt pattern, and you can use the bigger clutch, they called it 10.95" to differentiate it from the larger flywheel that took either an 11" or 12" clutch. Centerforce Dual Friction would be my choice.

If you can afford aluminum heads they would help take weight off the front end, that would be good. Then also you could run 10.5:1 compression with your available pump gasoline. It should be very easy to make 500 hp with such an engine, if you want that much. If you wanted only 400hp, a 360 would do quite well.

I would suggest finding a builder on the East Coast to build an engine for you. I am suspicious of mass-produced high performance engines.

I hope someone here can give a reference or two.

Whatever you do, ask here before you buy. Or send me a pm, I love to spend other people's money.

Good Luck!

R.

The good news is that you only have to sort this out once.

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I would look for a date code correct 340 block and stroke it for this particular car.

Sheldon

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Winner Winner Chicken Dinner....

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Hey Delta, Congrats on the 71 Cuda, where did you find it Berlin? Boston? Topeka? looks like a nice project

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A member just listed a 71 340 motor for sale in E Body Parts for Sale.....

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I would absolutely put another 340 in it, either 416 version or stock stroke.
Regards price, I have never understood why people say how much more a 340 is than a 360.
Just goes back to Mopar guys being ultra cheap skates in a ton of cases.
You can find a good 360 block for 100-200. You can find a good 340 block for 500-700.
Other than that trivial difference( in the whole scheme of building a motor and putting it in a 30-40 thousand dollar car like the OP)...The difference amounts to next to nothing
If someone is going to whine about 4 or 5 hundred bucks difference in buying a block and then building a motor with it being a make or break thing, they probably have zero business starting such an undertaking in the first place.
If it came with a 340, try and put one back in it.

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That's a rare/special car, weather you decide to install a close replacement now (or not) I would still recommend procuring the best/most accurate replacement you can find even if you keep it under the bench and decide to install something else. 1971 340's also have some one year only parts that you should also try to locate while you can (short list of larger items below).

1971 4972s Carter Thermo-Quad Carburetor
DR1114429 Idle Stop Solenoid
1970-1971 340 Air Cleaner
1970-71 Valve covers
1970-71 340 Oil Pan (294 stamped into the bottom)
1971 intake manifold- Casting # 3512100
Exhaust manifolds, casting #3418621 Drivers Side & #3418623 Passenger Side (the hard part is finding both with casting dates prior to your cars SPD)

You can learn more about correct parts details (Here ).

As far as a replacement 340 block goes your choices are pretty straight forward, most opinions will vary but the following are my personal choice list, my most to least favorite in order:

1. Find the original numbers matching block (long shot but nothing else will be 100% "correct" )

2. 340 block, warranty replacement or service block. I like these because the casting date doesn't matter so much and it won't have another cars VIN sequence number on it.

3. 340 block from another car which has an assembly date before and close to your cars scheduled production date.

4. 340 block from another 1971 model year car (any date)

5. 340 block, any year casting you can find

6. 340 block, new Mopar replacement "Resto 340" block

7. 360 block, any year

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I have all those parts, plus the warranty 71 block. Any chance of you shipping the car to me??? PLEASE!!

why not, maybe one day I decide to sell it
it already happened once, I bought a car in US, shipped to Europe, and then sold it and shipped back to US
We have one global market, because of internet

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So do I ademon, Im guessing niether one of us us getting that Cuda

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waiting for engine, next to my other mopar project (which is waiting for engine too )

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Alrighty then! Please add me to your bidder list

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So do you have the fender tag or Broadcast Sheet for the Cuda? If so could you post pics?

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You are lucky that broadcast sheet is under the seat. That's a wonderful Christmas present! Did your Cuda come factory equipped with rear window louvers? That is going to be one sexy car when finished.

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Is there anything special or rare about thic car?

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ABSOLUTELY Special
340/4speed
Great Color/Cool Interior/rallye gauges/vinyl top/louvers/spoilers....
This is a great 'Cuda, find a good 340 block and bring her back to life
I love it.

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another 340 is the answer...hell of a better motor than a 360

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I was going to post "Dont laminate the sheet!" But I guess Im too late. Be sure to make several high resoloution scans now, sometimes the inks can fade or run when sealed into the plastic like that.

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In the for sale section you just "reply" to the last post. Put your own title in it, though.
R.

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... A cheap (free?) 318 with a stroker crank installed is 390 cubic inches, no slouch & should rev up quickly just like a 340...

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Can a 318 breath well enough to make power with a stroker crank?

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I guess we'd have to ask someone who has one? Sounds like it could be a problem with 2.02 intake valves or larger... If I were building a 390 I'd put a set of Mag heads (1.92 intake??) & port them. They'd flow fine for 390 c.i. You can bolt LA covers on Mag heads, to dress it as a 340. Only hardcore Moparts guys would likely sniff out something unusual (no X or J or heat crossover. Pic of my LA 360 with Mag heads dressed as a 68 340.