340/drivetrain build advice

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ColoMopar

ColoMopar

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I hope I have this in the correct forum. Maybe the mods could move it if not. Thanks!

The Duster is here and seems to run okay with the 360 that someone put in it but, what's a toy if you can't play with it? So, I would like to build this 340 block that I have and drive a 340 Duster like the stripe says. I have been on this forum long enough to learn that building a motor is far more than what cam or heads to use. I've learned that the project starts with what you want the car to do then goes from the wheels to the fuel delivery. I have to admit that I am overwhelmed trying to figure this all out. I expect this to be a next winter project and would like to have a plan in place so I can begin gathering the parts.

So.....what do I want? I don't see this car as a drag racer nor well it be a daily driver. I see this car as a drive to shows, cruises, & pleasure type. I would like it to be very respectable on the road, probably line starts and below 90 miles per hour. I don't care about fuel economy for this car. I like the loppy throaty sound of power but I also would like the car to start relatively easy. Maybe EFI is in order, I am very intrigued with MSD's Atomic. I think this car should keep it's factory supension and tubbing isn't on my list.

Where do we start guys? Wheels, gears, power, what's the best combo? Once we've figured that out we can plan the motor.
 
You are going to get 100 different opinions...LOL! But This is likely what I would do. Sense you don't sound like your building a car for the drag strip. and basicly just a cruise nite type car, I'd keep the rear gearing somewhere around 3:55 to 3:91. I'd stick with a hydrallic cam. Lunatti Voo-doo series are nice cams. Comp. also makes some decent ones. What year 340 block, crank, are you starting with? I'd keep the compression around 10:1 or so, and you will still be able to run on pump gas. What heads do you have for the 340? What is your car, a 4 speed or an auto?
 
Its hard to beat the torque of a 4" stroke small block on the street. A hydraulic roller cam is a nice upgrade and aftermarket heads. Up at our altitude you can use more compression without detonation especially with aluminum heads. Also look at the FAST & edelbrock efi systems. For a street driver with the lousy gas we have efi is the best way to go.
 
fanofpetty said:
What year 340 block, crank, are you starting with? I'd keep the compression around 10:1 or so, and you will still be able to run on pump gas. What heads do you have for the 340? What is your car, a 4 speed or an auto?
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I have a 1969 block bored 40 over, magnifluxed and ready to go. That's it so far, no crank, no heads, just a block. The car is an auto (727) and I'll probably leave it that way. I love the thought of a 4 speed but I'm near 60 and not sure how long the knees would put up with clutch duty.
 
ok, so you have a good block for the foundation. I agree sense you need to purchase a crank, you might as well build a stroker motor. I personaly would spend the extra and go forged, not the cast junk that is out there. The automatic trans, is fine, maybe freshen it up with a TF-2 kit and a deep pan, and a street friendly converter, and your good to go.
 
If you switch to a clutch (4spd manual) then A Centerforce clutch set up is what you want. Easy on the knees and strong on the holding power.

I like Dartmans thinking with a 4 inch stroke roller cammed EFI power plant.
If you want to keep the 340 a 340, then your looking at deciding on what RPM range you wanna cruise in or at. This is a helping hand in cam selection and gear ratio.

If I ask what power level (HP) your looking for, could you target it?
If not, how about a target time slip number like, you want a 12 second ride or a 11 second ride.
 
rumblefish360 said:
If I ask what power level (HP) your looking for, could you target it?
If not, how about a target time slip number like, you want a 12 second ride or a 11 second ride.
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Not totally sure, I'm guessing 350-400 on the HP and maybe 12 seconds?? Sound about right?

I already have a 3:23 limited slip 489 case rear, also have a 742 3:55 open. Wouldn't be opposed to swapping out gears if needed. Also can play with tire size.
 
For mid 12's and no head work (AKA Porting)

Use a Hyd. Cam in the 244* range or advertised range of 292*. Use the valve springs recommended by the cam grinder. A RPM intake with a 750 carb (maker, your choice) , header w/-2-1/2 exhaust, stall converter to match (ask a Pro's advice like Frank Lupo or other) and a Trans-Go stage 2 shift kit. I'd use 4.10 gears with a 26 inch - 27 inch max tire. 3.91'smpossible with the shorter tire.

Upgrade your ignition. A MSD or equal with the stock recurved distributor will do just fine. Somewhere around 35*'s at 200-2400 max without the vacuum advance vacuum hose hooked up will do well. Rehook up the hose after setting. There is some play in that setting. The track will tell you if more or less is needed.

This should put you in the mid 12's firmly. Just remember everything is in the tune and settings.
In general, this combo should be good for about an easy 380hp. It is very similar to the MoPar create engine, a 360 @ 10-1 with the purple Hyd. 292/.509 cam that has dyno'd north of 400 with super comp headers (large tube) a d been in these pages in other fellas A body cars running a min. of mid 12's.

Others with more race rides have seen low 12'a and high 11's with that create engine.
In your full dressed A body, mid 12's are a state of tune and well applied torque. AKA, traction!
Enjoy, have fun! Rob
 
The use of a smaller cam of approx 280 advertised/230@050 will allow the 3.55's but only net you 13's. it will still be a strong performer but a little more streetable and Hwy. friendly.
You could also drop in carb size to a 650 for a super snappy throttle response.
 
Dont have anything to add Jim, but subscribed to this! Looking forward to following your progress as well as everyones input! Good luck with it!!
 
ColoMopar said:
Ya, that's what I'm thinking too. Good to hear from some Colo folks! I'll be watching for you in Golden this year!
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1 friday a month there is the Club Clash at Bandimere and its all street cars. You should bring your car up & just hang out with the mopar club. I will look for you in Golden as well this summer.
 
I used this exact build, a TF904 with Hughes 3000 stall, Transgo TF2, and a set of super stock springs; 8-3/4 with 3.91 Richmond gears with an Auburn sure grip.

Dynoed(bench) 410hp and 411lb lbs of torque.

In my 69 Dart I ran 11:98@112 with drag radials @ 18lbs

The machining is the most important part along with cleanliness.

http://www.compcams.com/information/Articles/Type/Chrysler/CC_MM0201-001.asp

If I didn't have that 340 I most assuredly build a stroked 360 and I would have had these guys build my motor based on my budget.(I want to go 125mph in the 1/4..who doesn't?)

http://www.immengines.com/home.php

Plus they are members here.
 
street car/cruise night.
.92 torsion bars,disc brakes,front sway bar,mopar performance rear springs,60 series radials,rebuilt front suspension.
now a warm 340 with a Lupo 9 1/2" converter,you'll be happy.
 
Thanks for all of the advice guys, I'm seeing several possibilities. There is one thing that we didn't talk about and that is the altitude where this car lives. I am in the Denver area and if I'm not mistaken that should have some consequences on how this should be built.

What do you guys think?

I also started another thread on the possibility of considering the 1.88 intake 308 heads for that same reason.
 
Watching this thread and liking the thoughts and ideas. I too am trying to figure out what to build for my 70 duster. I have a complete steel crank 340 (1972) with 1970 date code X heads on it. It supposedly runs but there is some slop in the bores, so it will be rebuilt. My car came with a 1968 4 speed setup and a 3.23 Sure Grip, so I will probalby keep them intact to save some $$$ for now.

Good luck with your choices!!!
 
http://www.aamidwest.com/enginequest/eq-cylinder-heads/chrysler-magnum-head/

I'm not sure of the price, but if you're buying iron heads, you might want to check these out. There are links to a recent Popular Hotrodding Magazine article and the stroker 360-based engine made 580hp...even though you're not building a 417" stroker, probably worth considering.
Also, recommend the book on rebuilding the 727 rebuilding book by Munroe http://www.bing.com/images/search?q...BC7F824C616982E6AEEE8D03C4E0F600C&FORM=IQFRBA

this link to the book. Built my first 727 using this book/Munroe's recommendations and added a TF-2 kit as previously recommended and it's holding up find behind a 600hp 493" RB-based engine. The TF-2 fixes the 2-3 shift overlap and has great shifting manners.
Good luck, let us know how it turns out.
:burnout:
 
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