430+hp 340 possibilities
- Thread starter Lurbieloo
- Start date
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Yeah and maybe that might be the direction I go. Not sure yet. Those are just the parts I currently have. To be honest I’d be happy with 400 hp, but was wondering what other guys have done or know to make 430-450 out of an iron head 340
AustinGriggs
Well-Known Member
My '70 340 on the chassis dyno made 279HP to the tire: 20% more is 330 at the flywheel. Exactly 100 shy of your goal. Now, where can that much power be found? This engine had factory pistons, crank, rods. New rings / bearings and the heads are factory J heads with minor bowl blending, the cam was a Hyd Roller that peaked at 5700rpm. This combination used an RPM intake, a 750 Holley, had headers, and 2 1/2 exhaust.
Pistons- upgraded both in weight and compression height as well as a slight dome could be a solid improvement. I would venture to say 35hp could be found there.
Head flow- Going far past where I stopped that go around would be necessary, upgraded valves and springs capable of the RPM to push past where mine nosed over. If you are really make the effort to neckdown the guide boss, open the pinch and the bowl up as well as mill the heads considerably another 35hp if not more depending on execution.
STILL... we are in the hunt for 30 more! This is where a better cam than I had is key and RPM is going to be desired past where mine was limited. No matter if you go FLAT or Roller; Solid be your easiest route to achieve that 430 number!
There is nickel and dime items here and there to pad the stats like carburetor, intake porting, valvetrain upgrades, balance/lightening, exhaust, tune and ignition. But for a factory stroke 340 and factory heads 430 is achievable but you are gonna have to want it and get it right! I hope this helps you in your approach to your admirable goal of not taking the easy button; Which is a 408 or a Gen III Hemi.
Pistons- upgraded both in weight and compression height as well as a slight dome could be a solid improvement. I would venture to say 35hp could be found there.
Head flow- Going far past where I stopped that go around would be necessary, upgraded valves and springs capable of the RPM to push past where mine nosed over. If you are really make the effort to neckdown the guide boss, open the pinch and the bowl up as well as mill the heads considerably another 35hp if not more depending on execution.
STILL... we are in the hunt for 30 more! This is where a better cam than I had is key and RPM is going to be desired past where mine was limited. No matter if you go FLAT or Roller; Solid be your easiest route to achieve that 430 number!
There is nickel and dime items here and there to pad the stats like carburetor, intake porting, valvetrain upgrades, balance/lightening, exhaust, tune and ignition. But for a factory stroke 340 and factory heads 430 is achievable but you are gonna have to want it and get it right! I hope this helps you in your approach to your admirable goal of not taking the easy button; Which is a 408 or a Gen III Hemi.
roccodart440
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67autocross
A new iron curtain drawn across the 49th parallel
K.O. SWINGER
Meeting in the alley since 1976
My current 340 comes in right around 400 flywheel horsepower. It goes like this T/A six pack pro comp heads competition valve job heads purple cam 242 at 50. 498 lift 10.1 compression 391 gears 26 in tires, before this current setup I ran a m1, 850 thermoquad and cleaned up X heads with the 292 purple cam set up this set up made a little bit more on the top end but my current one is probably just as fast because it pulls so strong through the middle, my point is with a little more compression and a pro Port job 430+HP is very obtainable.
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512Stroker
We are all here because we are not all there.
Current NHRA Stock Eliminator 340's will make 500 hp with stock blocks, heads, intake, CR. No porting is allowed.
And of course it works with;
@512Stroker -
I will say these guys that run in that category really take advantage of it all.
furrystump
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He would know, he built my heads. I’m at 410 CI and 12.2 to 1 so not really street friendly and I’m at a little under 400hp. Now my motor is pretty underperforming due to having to run stock 68 intake and exhaust manifold castings. The intake is somewhat modified. As to cost, not crazy, but to build it again, $10,000?
K.O. SWINGER
Meeting in the alley since 1976
How can that be possible? To hear people talk around here sometimes those heads are garbage nothing more than door stops LOL
my neighbor's F/SA 68 340 Barracuda made 440 hp on the dyno, it can run a second under the index...borrowed another AVS carb from Steve Wann the engine made 465 hp...Visit another stocker friend today....working on a 72 Charger for someone else...putting new quarter panels on it...and inter fenders in the front.
Said they had shipped the 273 back to get repair....dinged a valve...owner wanted beehive springs..but the stock valve keeper had 4 grooves..so they had to replace all the valves....Valve job cost over 2k....
Cheap class...lol
Said they had shipped the 273 back to get repair....dinged a valve...owner wanted beehive springs..but the stock valve keeper had 4 grooves..so they had to replace all the valves....Valve job cost over 2k....
Cheap class...lol
512Stroker
We are all here because we are not all there.
A friend of mine is an engine builder for some of the top Mopar D and F stock racers in the country including National Champions and current record holders. I have seen the 340 dyno results right at 500 hp. These cars run in the mid 10's. He built my 340 and it made 442 hp corrected with balanced stock rotating assembly, NHRA legal X heads port matched manifold and a Comp XR274HR cam. He spoon feeds me little bits of building info but he not giving up much.
These engines a very expense but the work and will pass an NHRA tear down.
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K.O. SWINGER
Meeting in the alley since 1976
That's really cool! Oh I agree 100% the potential for a 340 x or j headed motor in the right hands is ridiculous or at least very impressive. I have also seen 340 powered stock eliminators running in the mid tens it never ceases to amaze me. Short stroke mopars have kind of fallen by the wayside over the last 10 years in lieu of strokers I get it they're awesome. But I've been running 340s for over 40 years and the little overachiever can still be a lethal weapon in the right hands.
67autocross
A new iron curtain drawn across the 49th parallel
You should just get member RAMM to do the build for you…he could get you the power you want …and with the current US to Canadian dollar exchange rate the cost would likely be not to bad…
D-mailman
Well-Known Member
You can do it . My build : .030 over 340 , Speed Pro forged 9.0 to 1 for pump gas , stock forged crank, stock rods , 915 J heads, 2.020/1.600 , ported to 260 CFM , Mopar Performance 284 / .528 Mechanical camshaft , 1.6 HS rockers , Holley Strip Dominator, Holly Carb 4779 750 mechanical secondaries , Hooker Super Competition headers ,1 3/4 tubes . 441 HP . Yes, you can do it .
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B3422w5
Well-Known Member
340 is capable of making plenty of power in stock stroke form with factory iron heads.
I have mentioned this before on here, but a buddy of mine has been 9.60’s at 2700 ish pounds with a 20 over 340, and 1.92 valved iron heads. No kidding. Without much compression.
There are guys on here i am sure that know the car. He spins it 9000-9200 with aluminum rods. Extremely impressive, to say the least
I have mentioned this before on here, but a buddy of mine has been 9.60’s at 2700 ish pounds with a 20 over 340, and 1.92 valved iron heads. No kidding. Without much compression.
There are guys on here i am sure that know the car. He spins it 9000-9200 with aluminum rods. Extremely impressive, to say the least
MOPAROFFICIAL
Oogliboogli
Yes.
Using a 2.02 intake valve any 360 LA head intake port can be ported to flow in the 260's cfm or better. The exhaust kinda stops after 190's ,maybe more for others who skip hard seats. I've got into 200 not having the hard seat. Retains the throat material is why.
However It will run okay on the street in a 4spd/Manual transmission car and not be so fun with an automatic.
9secRR
Well-Known Member
Car 8479 right lane. 340 with iron heads
He said budget build!
Pics and slips?
B3422w5
Well-Known Member
its Vic Bloomer’s car. There are plenty of guys on here who know him and the car. A body Barracuda.
Not to sound cocky, but i dont need to prove anything, my credibility is super good.
B3422w5
Well-Known Member
Vic’s car…
I guess if he's spining it up to 9000 it ain't no budget build. Good 1.5 motor.
B3422w5
Well-Known Member
he built it himself, ported the heads himself, probably actually wasn't very expensive at all.
He broke it a while back, think its back together again now
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