Building a nice 340

I am getting ready to build a 340 for street use. Is there an article out there of a nice built 340 that I can take a look at before I start my project. 340/727/3:55 a body. Thanks for any directions that can be offered.

you need to define nice?
having said that there is more than enough experience on this site (not me)to tell how to build to your target.
..i will say use a 904,save 35 lb. and increase efficiency and useable horsepower.

I don't know of any articles on SB Mopars but I have owned and race several of them including helping a former several time 340 stock NHRA record holder I've been building and racing Mopars since the early 1960s, early hemi, M.W. wedges, street wedges and 2nd gen Hemi PM me if you want some particulars and suggestions for a combination

Stroke it!!

This is my 340. Very streetable!

http://www.forabodiesonly.com/mopar/showthread.php?t=241854

They really need cam and headers. Stroking may be needed but a 340 can really rev. Had the best luck with a 480ish cam and tri-y's. It was a beast! Excellent street racer, 4 speed 3.55 BCuda.

-Daty

The absolutely first thing to do is spend some money on pistons that don't weigh as much as a 427 chevy piston. A 500 gram piston should be your first stop.
Second ditch the stock rods and get some 7/16 bolt 650 gram rods. The stockers weigh 758. Again bigblock chevy weight.

Take out 300 grams per cylinder and the engine will come alive. 300 x 8 = 2400 grams, which is equal to 5.3 lb. That's a lot of reduction in rotating and reciprocating mass. It'll also allow the crank counterweights to be lighter.

These two changes make everything else that you do to the engine, better.

R.

One other thing: Build a zero-deck engine. Piston to the top of the block, nothing more. That way you can use a modern combustion chamber and set the squish with the head gasket.

The idea is to keep the stock heads and such, i am hoping just to get maybe 375 horse.

On todays pump gas with iron heads I wouldn't run more than 9.75 to 1 compression ratio
Building a 4 inch stroker motor will reach your goals easily
With your present (stock stroke)combination I would use a Eddy RPM air gap intake and a good 750 CFM Thermoquad and a cam based on the peak torque RPM goals BTW, the last two NHRA legal 340 stocker motors I built and dyno tuned made 420 HP with the J heads and 430 HP with X heads My freind who held the NHRA E and C stock records made a little more power(450 HP) on the same dyno as mine did He did a lot more parts testing to get those results though

I put together at least 4 340 over the years with mostly stock parts including the early hi compression pistons.

Then in 2007 I cracked a cly wall and leaked water. So I had to use a spare block I had with a stock bore and cast crank. I ordered KB243 pistons from Summit. Took like month to get stock bore pistons. I used heavy stock rods.
I had already bought the open chamber eldbrock heads a couple years earlier.
The pistons stuck up .029" above the deck and worked well with my eldebrock heads for early higher compression pistons. Pistons are way lighter than stock. I did not re balance the assembly. Not saying this was right but I did not spend the time or money to have it balanced, it's just a street car to me.

Right away I could tell it had lighter pistons in it. It revved way quicker than any of my other 340 motors from years gone by. I'm sure the eldebrock heads helped some too.

7 years later that motor is still in my car running great. Since then I have driven it at 120 mph for miles at a time out at bonneville Utah in 95 degree weather,3 times, 3 different years! Driven it several times in Reno and Vegas in 115° heat. Been to the top of pikes peak with it twice and have driven it all over the country since then.
It has over 25K miles on it now and is still the best running 340 I have ever driven and is was a low buck rebuild. The pistons only cost like 250 bucks for a set of 8.
I honed the stock bore by hand and the rings sealed up fine, it don't smoke or burn any oil. One tough 340 I'm here to say, trying driving your car at 120 mph for miles at a time in 95 degree weather, it beats up your car and motor up but good.

I did the whole build myself and didn't need to have any machining done. True low buck rebuild that has lasted. This motor is run on 91 octane unleaded with no ethanol.

Why why why limit yourself with stock heads? The combustion chamber is a joke.
Talk to Brian at IMM, OU812 on this board. Seriously, there is a better way than using the crappy stock combustion chamber. Of course it can be made to work, but the Mag head chamber is better, enough so that it's worth pursuing. The EQ iron heads with the Mag chamber are one way.

But, even if you decide to saddle yourself with the stock heads, those 720 gram stock pistons have to go.

R.

If you are planning on an all stock set of heads, no porting, you need more camshaft to reach your goal. Simple bowl porting, clean up and port opening work will do wonders for improving performance.

Intake, Headers? Both make a difference.

Agreed, lighter pistons./rods make things easier on other components as well. Will likely rev quicker too.

Ported heads can get there with nothing more than a XE268H or Voodoo 268. Non ported would require a larger camshaft.

Here's an old build from a mag with some fantasy output numbers. Same engines built made 330-350hp on other dynos in the area.

http://www.moparmusclemagazine.com/techa...no/viewall.html

..Stock heads (even 1.88 intake J heads) will flow 400hp.
I have seen stock style 300hp builds run mid thirteens with
a gear and a converter.

Thanks for the article, I might think of a stroker but want the motor to appear more stock than a hot rod.

Quote:

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Thanks for the article, I might think of a stroker but want the motor to appear more stock than a hot rod.

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Call Dave at Hughes Engines and pick his brain.