340 Build

bowtie468 · Member Joined: 12 Jan 2008 Posts: 22 1025.56 points

Hi guys I usually post in the Big Block Chevy fourm, I am doing a 1970 340 Mopar for a friend that came out of a 70 Duster that he is also restoring. Heres the build :.03 over , stock double eyebrow pistons , Comp Cam #20-223-3 .477 int, .480 exh, dur @ .05 int 224, exh 230, induction Edelbrock Performer RPM intake , Holley 650 double pump. exhaust hookers 5901hkr 15/8 od by 34" 3" collector. Ign. he has shelved the points distributor and bought the Mopar performance electronic ignition. My question as I have built many Chevy Small and Big Block engines but this is the first Mopar. I must say that it looks just like a small blockChevy, but I like the valve angle in the heads. Is there anything that I need to know that is specific to this engine prior to start up? What should I time this thing at for starters and what should the total timing be set at. I will be staying with the stock holley jetting unless it seems to want more, he wants this as a driver, he will be driving this car, it has an automatic and 3.23 gears. Any exhaust reccomnaditions,or anything that you Mopar experts can add would be appreciated

FRITODAVE · Posted: Mon Mar 24, 2008 10:22 pm Post subject:

An engine is an engine no matter who makes it. Those engines need compression. Hopefully it has the original closed chambered heads and not the junky open chamber ones. That engine will probably peak out at 5500rpm which is good. 30* timing is about the most it will need. My personal thought is the double pumper might be a bit much with your gear ratio. Stock jetting should be fine up to about 2000Ft. In the picture it looks like there is no cam lube. That kind of scares me Confused

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bowtie468 · Member Joined: 12 Jan 2008 Posts: 22 1025.56 points

Thanks Dave believe me there is plenty of cam lube on that cam, I had hand rotated the engine to prime the oiling system, before the intake went on I relubed the lobes. Yea I now that an engine is an engine, I just didn't want to overlook something specfic to the mopes. Thanks again I will post the outcome after I install the engine and fire it up. I couldn't talk him into steeper gears, as he wants to drive this thing alot as his dad left this car for him!!!!!Thanks again

bowtie468 · Member Joined: 12 Jan 2008 Posts: 22 1025.56 points

It lives, short video of 340 Mopar in above pictures runnin

squeeezer · Posted: Fri May 23, 2008 9:58 am Post subject:

sounds good

wagon train · Posted: Fri May 23, 2008 5:46 pm Post subject:

bowtie468 · Member Joined: 12 Jan 2008 Posts: 22 1025.56 points

First time this car has moved under its own power in 20 years, again the 340 Mope in above pictures.

ARK · Newbie Joined: 10 Nov 2009 Posts: 4 267.08 points

A HOLLEY IS NICE BUT A BIG THERMOQUAD WILL REALLY WAKE UP YOUR SLEEPY DUSTER . ONE OF THE OLD 800 CFM UNITS YES EVERYONE WILL TELL YOU ITS TOO MUCH FOR THE 340 BUT TOO MUCH IS JUST RIGHT FOR THOSE OLD DUSTERS. HAD A COUPLE OF THOSE IN THE LATE 70S ALWAYS RAN BEST WITH A THERMOQUAD ON A STOCK 4 BBL MANIFOLD (M1 IS SUPPOSED TO BE THE HOT SET UP NOW) WITH THE PURPLE CAM SHAFT. TRY 12 DEGREES INITIAL WITH 35 DEGREES TOTAL ADVANCE YES THIRTY FIVE DEGREES TOTAL ADVANCE . N9Y PLUGS GAPPED ABOUT 40 YOU MIGHT WANT TO FIND THE ORANGE CONTROL BOX FOR YOUR ELECTRONIC IGNITION .FACTORY NUMBER 4120505 UP TO 6000 RPM AND NUMBER 4120534 UP TO 8000 RPM IF MEMORY SERVES ME RIGHT.MANUAL SHIFT KIT IN THE 727 AUTOMATIC.
PUT A SET OF 1 3/4 HEADERS WITH DUAL EXHAUSTS CROSSOVER PIPE AND A PINION SNUBBER ON THE REAR WITH SOME 9 INCH TIRES AND YOU CAN SURPRISE THE LOCAL BOYS WITH THEIR TA S AND MUSTANGS DEPENDING ON THE RUBBER YOUR RUNNING SHOULD BE GOOD FOR MID TO LOW 13S .

jeep_406 · Posted: Tue Nov 10, 2009 10:44 am Post subject:

Ran a 1969 Dodge Dart Swinger with a 340 back in the 70's. Went 13.7 @ 101 MPH. Had a 600 DP Holley with a set of headers and a 727 automatic. Came from the factory with good heads, 10.5 - 1 compression. Ran a 3.55 gear.
The car didn't like more than 30-32 degrees total timing. 1971 was the last year for the good heads. Used 318 heads after that. As I remember there was a fix to help the oiling system but it was too long ago to recall.

squeeezer · Posted: Tue Nov 10, 2009 8:25 pm Post subject:

im 1/2 way through my 340 project for a buddy with a duster
currently looking at a distributor set-up for it
i have a 600 dble pumper
235 duration cam 108lsa

its a 4 speed 4;11 geared 70 or 71 duster
im hoping for 350 to 370 horse 5600-5700 rpm motor
as im gonna dyno it (owner is pretty excited....first time)

ARK · Newbie Joined: 10 Nov 2009 Posts: 4 267.08 points

Think your buddy would be happier with more duration and lift. Those 411s are going to make you run out of power before you run out of track. p4120233 right out of the mopar catalog has 292-292-76 with 508 lift I&E centerline 108 and I dont think the 600 holley is going to cut it either if I had to use a holley it would be at least a 750 double pumper with a phenolic spacer under the carb to avoid heat transfer problems..Frankly I have never seen an over carbed 340. Remember to put an electric fuel pump at the tank.
As far as the sparker goes p3690426 is the number for the complete kit. 229.95 from Mancini Racing
Distributor with performance curve installed ,adjustable vacuum advance, orange box, ballast resistor, harness and instructions good for 6000 rpm from mopar. Orange Box alone is 4120505 if you already have distributor. You should recurve it or have it done to bring advance in by 1200 rpm. hope this helps

squeeezer · Posted: Wed Nov 11, 2009 2:51 am Post subject:

ya this is my budies first keeper car
he is already talking 3:55 gears or so
for freeway driving

350 horse motor will make him shit himself
he had driven this car maybe a handfull of times

this is a starting point
a good one i say
he just wants a driver at this point there are a lot of things that can be better/impro ved

jeep_406 · Posted: Wed Nov 11, 2009 12:15 pm Post subject:

I never put my 340 on a dyno but I remember stories that Mopar underestimated horsepower readings for insurance purposes. I thought they were supposed to put out around 325 in stock trim although they were rated at 275.

ARK · Newbie Joined: 10 Nov 2009 Posts: 4 267.08 points

The 355s should let it live on the highway and let him get all the way down the track but he will probably be in the 14s with that cam. Still he can learn as he goes and add the proper accesories as he gets the urge to go faster. As for the power rating of the 340 the rumor was they gave the power at the rear wheels when everyone else was giving the engine only. I have no proof as I said it was a RUMOR but the way these things used to eat stock sb chevys with supposed 350 horses I tend to believe the rumors.
I hope your friend enjoys his new ride , please post your first run at the track and take a picture of his ear to ear grin.

squeeezer · Posted: Wed Nov 11, 2009 8:10 pm Post subject: