Moparts
Let's talk 340 builds......
Posted By: Chris2581
Let's talk 340 builds...... - 09/27/09 12:57 AM
Since I'm going to put my Demon back as a street/strip car,I've been planning on a 440/727 combo,but since I have a real nice 1972 340 forged steel crank/rods,and my Demon is a original 340 car,I've been thinking of going that route instead.I'd like the car to run 11.50's with 4.10 gear.I'll be using a 727 with my tried and true Turbo Action 3800 converter.I'm open to suggestions as I really haven't paid much attention to the small block stuff in a while.I can say what I DON'T want....
No roller cam,strokers,expensive aluminum heads(like B1Ba's or W8's etc)
So what you say??
Posted By: goldmember
Re: Let's talk 340 builds...... - 09/27/09 01:03 AM
More gear,let TA restall the converter,good compression and the best heads you can swing.Or forget that and add a 4" arm and leave the converter,gear alone. A decent set of ported factory heads are fine.
Posted By: S/ST 3040
Re: Let's talk 340 builds...... - 09/27/09 01:07 AM
This should be interesting.
Posted By: MoparJoe
Re: Let's talk 340 builds...... - 09/27/09 01:37 AM
255@.050/.600 solid, Edelbrock heads, victor 340, get the converter as loose as you can, with 4.88's this has been 10.90's in a swinger.
Posted By: 451Mopar
Re: Let's talk 340 builds...... - 09/27/09 02:56 AM
Turbo, supercharger or Nitrous?
Posted By: Chris2581
Re: Let's talk 340 builds...... - 09/27/09 03:11 AM
No turbo blower or funny gas.Street/strip engine. I know it can be done with a 440,I'm just interested if there are any stock stroke 340 combos that can run the number,all I'm looking for is 11.50-11.60's and still be able to reasonably drive it on the street.No 4.30's or lower or super loose converters.4.10 will be the gear regardless of what engine I use.
Posted By: ProSport
Re: Let's talk 340 builds...... - 09/27/09 03:25 AM
My old 340 Scamp was .030 over(346), stock crank and rods, stock oil pan, MP 557 purple shaft installed at 110(would have been quicker advanced), Performer RPM or single plane, I forget which single plane I had but it wasn't any quicker than the RPM, 750 double pumper, mechanical water pump(probably slowed it down 1.5 tenths or more), ported Edelbrock heads. This car could be driven all day and ran 11.70's with more potential. Compression was around 11 to 1 if I remember correctly.
Posted By: 451Mopar
Re: Let's talk 340 builds...... - 09/27/09 03:26 AM
It is doable with cam, compression and airflow, but I think it will be more strip than street?
Just start with the best flowing heads you plan to use, then run the most compression your fuel will tolerate, and an aggressive cam, that will produce the most useable power in your power band.
Something like Edelbrock RPM heads, 10.5 to 11.0:1 compression, and maybe a cam around 245+ duration, with 0.600" lift?
Posted By: ademon
Re: Let's talk 340 builds...... - 09/27/09 05:43 AM
get the RHS heads, do a little port work. get a solid in the 248 @ .050 range or a bit more, rpm air gap, or single plane/ with at least a 750 cfm carb, i like annular boosters. better have at least 10.5 cr and a good set of headers and free flowing exhaust. But I would stroke it put a mild hyd cam, use stock rockers, 3.55 3.91 gear and still run mid 11's with less wear and tear
Posted By: Brian Hafliger
Re: Let's talk 340 builds...... - 09/27/09 05:45 AM
I did a nice little 340 build not too long ago, mildly ported eddy heads to speed up the air in the ports and for more flow, 10.5:1, 244-252 @.050 solid FT cam, victor intake, 950HP carb, and 1 3/4 headers. It made 455 HP on our DTS dyno and it ran very well in the car. He did run it I think, but the chassis was about as stock as could be and it was geared kinda high.
I think it ran high 11's or low 12's in a mostly stock Dart and a street converter (11").
I rode in it, and it did pull very hard!!
Posted By: justinp61
Re: Let's talk 340 builds...... - 09/27/09 06:30 AM
My 340 ran 7.24 in the 1/8 in my 3300# street/strip Dart. It was 11.2-1, Ross flat tops, Eagle I beam rods, factory steel crank, Hughes hydraulic 237/242 @ .050, .586/.592, Quick Fuel Q-750 on a Weiand X-Celerator intake, ported Edelbrocks, 4.30 gears and a 4400 rpm stall. It should've gone 11.40s in the 1/4.
Posted By: goldmember
Re: Let's talk 340 builds...... - 09/27/09 06:39 AM
That makes sense to me,we went 11.20's with factory iron heads 15 yrs ago with similar combo at 365"The fact that he doesn't want to add more gear converter,etc. I think he'd still have a problem but the 4" crank covers alot of problems.I'd rather add inches than change a number of parts to acheive a goal. My mild Duster runs 11.50's with 2bbls of carb and 2.4 rear gears and it drives 700 miles at a stretch without issue. Lot's of ways to get mid 11's.
Posted By: Quicktree
Re: Let's talk 340 builds...... - 09/27/09 09:34 AM
Quote:
That makes sense to me,we went 11.20's with factory iron heads 15 yrs ago with similar combo at 365"The fact that he doesn't want to add more gear converter,etc. I think he'd still have a problem but the 4" crank covers alot of problems.I'd rather add inches than change a number of parts to acheive a goal. My mild Duster runs 11.50's with 2bbls of carb and 2.4 rear gears and it drives 700 miles at a stretch without issue. Lot's of ways to get mid 11's.
stroker is the way to go Chris and still have street manners with the rules you have put in place. if not you will have a very lumpy street car.
Posted By: Chris2581
Re: Let's talk 340 builds...... - 09/27/09 12:17 PM
Ok this is what I want to hear,so keep the ideas coming.The 4" crank makes sense..are there any forged steel ones?? I'm looking at reliability as well.If the 340 ends up being more $$$ than the 440,I will go 440.The car has a Dana 60,so I'm not into swapping gears,and I'm not buying any more converters.
Another reason I'm looking at this is I used to run small blocks 20 years ago,and I already have a big block car,so it would be nice to have one of each.
Posted By: Hemiroid
Re: Let's talk 340 builds...... - 09/27/09 12:28 PM
Quote:
Ok this is what I want to hear,so keep the ideas coming.The 4" crank makes sense..are there any forged steel ones?? I'm looking at reliability as well.If the 340 ends up being more $$$ than the 440,I will go 440.The car has a Dana 60,so I'm not into swapping gears,and I'm not buying any more converters.
Another reason I'm looking at this is I used to run small blocks 20 years ago,and I already have a big block car,so it would be nice to have one of each.
A basically stock iron headed 440HP with a cam change gets it done with the gear/vert specified.
Posted By: Quicktree
Re: Let's talk 340 builds...... - 09/27/09 12:37 PM
a stroker 340 with eddy heads and a mild cam and your there. plus lose over 100#s off the nose. plenty of steel stroker kits available.
Posted By: HotRodDave
Re: Let's talk 340 builds...... - 09/27/09 04:01 PM
I think it can be done with a stock stroke but the cam has to be perfect (relatively short duration fast lift lobes to get the tq up and still make up some time on the top end), the carb has to be perfect, you have to have just the right headers... to get it to work with your gears and converter it will take a lot of fine tuneing and experimenting. If you go 4 inch stroke it is a cake walk. I don't really care for the old open chamber heads but even they will work if you port them a little and run the big stroke
Posted By: emarine01
Re: Let's talk 340 builds...... - 09/27/09 04:16 PM
Posted By: 340B5
Re: Let's talk 340 builds...... - 09/27/09 04:23 PM
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"Veeery interesting"
Posted By: 65signet
Re: Let's talk 340 builds...... - 09/28/09 08:55 PM
A friend has a 69 dart, ootb eddys around 550 lift cam maybe 11-1 small headers, runs 11.70s
Posted By: S/ST 3040
Re: Let's talk 340 builds...... - 09/28/09 09:24 PM
Using 4.10 gears and a 26" tire, will equate to 6040 RPM, driveshaft
speed and require 365 HP to get a 3200 lb. car to 114 MPH.
IIRC a T/A 3800 will tylically flash around 5000 RPM.
It is entirely doable but, cylinder head work and camshaft selection
will be critical.
Posted By: theclutcher
Re: Let's talk 340 builds...... - 09/29/09 02:21 PM
will need a bit more gear than 4.10.
get trap rpm to 6500ish with gear/tire combo imo.
Posted By: S/ST 3040
Re: Let's talk 340 builds...... - 09/29/09 02:29 PM
I gave driveshaft speed as converter slippage is unknown.
5% slip would be 6360 engine RPM. I would expect no more than
5% from a T/A 3800. My T/A 4600 slipped less than 5% albeit, in
a lighter car with more gear and RPM.
Posted By: theclutcher
Re: Let's talk 340 builds...... - 09/29/09 03:27 PM
keep forgetting about your guys converter slip.
think a 4.30 would be too steep?
Posted By: S/ST 3040
Re: Let's talk 340 builds...... - 09/29/09 03:35 PM
NO.....not too steep at all but 4.10 is his self-imposed gear.
Posted By: S/ST 3040
Re: Let's talk 340 builds...... - 09/29/09 03:48 PM
Here's the dyno sheet from last year's EM 345"
10.4:1 flat tappet, pump gas
Obviously the INDY 360-2 heads are over-kill for 365 HP
but, at least it shows a 340 is more than capable of
meeting his goals with his 4.10 gear. (HP @ 6000)
Posted By: sixpackbee
Re: Let's talk 340 builds...... - 09/29/09 04:02 PM
A well done set of 894's, a good solid lifter, and around 10.5 CR should get you where you want to be. It would not hurt to put more screw to it down the road.
Posted By: S/ST 3040
Re: Let's talk 340 builds...... - 09/29/09 04:11 PM
Quote:
A well done set of 894's, a good solid lifter, and around 10.5 CR should get you where you want to be. It would not hurt to put more screw to it down the road.
There's no way an OEM will even come close to making any power. 
Posted By: sixpackbee
Re: Let's talk 340 builds...... - 09/29/09 04:24 PM
Quote:
There's no way an OEM will even come close to making any power.
So say you. 
