Stock 340 dyno tests?

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Here's a low cr 2bbl 318 with headers dyno's 182 hp, even if you add a decent amount of cr you get a 3-4% power increase so 190 hp with headers.

https://www.motortrend.com/how-to/mopp-0312-318-long-block-bolt-ons/

Here's a low cr 360 at one point around 3:45 time mark, stock low cr, 1.88 valves, 2bbl cammed with factory 360 4bbl intake and exhaust manifolds and a Qjet makes 264 hp. That's basically the 340's 275 hp power number but without cam cr and 2.02. I know the 360 got 20 cid on a 340 :)

When he added a similar cam as a 340 xe250h and 2.02 heads with a bit of work so maybe on par with x heads but with headers and aftermarket intake but still low cr made 339 hp.

What did a 340 make? Who knows but we do know they were fast.

 
RLF Cuda said:
...Interestingly, Chart 6 on Page 1332 show what ET is possible with the proper chassis and transmission setup. A stock 340 with a race weight of 3250 should turn 12.70's in the quarter mile. Stock with tires, torque converter and good driving. Not bad.
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I wish I could find my old DC book. I remember the chart that told you what to do to go 14.0, 13.5, 13.0, etc....suspension, tires, weight, engine mods.
 
I’ve only run maybe 10 340’s on the dyno.
Never a “stock” one.

This was the mildest one, originally built in about 1987, then freshened up I’d say around 14 years ago, which is when it was tested.

Was originally a low cr cast crank motor that got cast replacement pistons for the earlier engine.
587 heads that had 2.02 intake valves installed, and bowls blended back in 1987(one of my earliest “porting” jobs).
For the freshen up it got a Comp 268H cam.
The std performer intake and Holley 650DP were reused, and it was tested with 1-5/8 x 3 headers.

Made 378tq/343hp.

It resided in a lil red express truck with a ta hemi converter and 3.55’s.
 
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PRH said:
I’ve only run maybe 10 340’s on the dyno.
Never a “stock” one.

This was the mildest one, originally built in about 1987, then freshened up I’d say around 14 years ago, which is when it was tested.

Was originally a low cr cast crank motor that got cast replacement pistons for the earlier engine.
587 heads that had 2.02 intake valves installed, and bowls blended back in 1987(one of my earliest “porting” jobs).
For the freshen up it got a Comp 268H cam.
The std performer intake and Holley 650DP were reused, and it was tested with 1-5/8 x 3 headers.

Made 378tq/343hp.

It resided in a lil red express truck with a ta hemi converter and 3.55’s.
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Change for change a 440 will make much more power. Go to any bracket race look at the mopars then see how many have 340s or 440s. Unless your class racing, CUBES is the winner. I’ll take a 572 over a 408+ anyday.
 
Ceedawg said:
Change for change a 440 will make much more power. Go to any bracket race look at the mopars then see how many have 340s or 440s. Unless your class racing, CUBES is the winner. I’ll take a 572 over a 408+ anyday.
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predeng2.jpg

Get some. :D
 
fishmens67 said:
View attachment 1716168336
Get some. :D
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Predator headed 572 WILL make more HP with same equipment, why limit oneself to cubes? but don’t stop there get a BAE top fuel engine. If small blocks were faster don’t ya think they’re be in the top classes?
Don’t get me wrong I like the little engines but dollar for dollar the big engines dominate.
 
Ceedawg said:
Change for change a 440 will make much more power. Go to any bracket race look at the mopars then see how many have 340s or 440s. Unless your class racing, CUBES is the winner. I’ll take a 572 over a 408+ anyday.
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I mainly agree but if you put 550 hp parts on a 340 or a 440 you basically get 550 hp, the recipe ain't that different. Problem with smaller displacements you run out of reasonable rpms to build larger power why a lot go 408, at some point bore size is an issue to. But with Big Block you can put together 650/750+ hp combos relatively easier and probably for similar money as 550 hp small block making it the value choice.
 
Wait we're comparing displacements, as they pertain to full on race engines? I thought this was a stock 340 dyno tests thread?
 
Mean416 said:
Wait we're comparing displacements, as they pertain to full on race engines? I thought this was a stock 340 dyno tests thread?
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9 months and 6 pages the thread is bound to die or go off the rails or both.
 
273 said:
I mainly agree but if you put 550 hp parts on a 340 or a 440 you basically get 550 hp, the recipe ain't that different. Problem with smaller displacements you run out of reasonable rpms to build larger power why a lot go 408, at some point bore size is an issue too. But with Big Block you can put together 650/750+ hp combos relatively easier and probably for similar money as 550 hp small block making it the value choice.
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Yes my point, if I’m spending that kind of money for the engine shown I want the biggest baddest one for the buck.
 
273 said:
I mainly agree but if you put 550 hp parts on a 340 or a 440 you basically get 550 hp, the recipe ain't that different.
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The recipe certainly is different, a 550hp 440 is a mild build and the 340 would be considered on the outer limits.
 
fishmens67 said:
The recipe certainly is different, a 550hp 440 is a mild build and the 340 would be considered on the outer limits.
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A 550 hp 440 is mainly consider mild cause it can spin less than 6000 rpms to make it.

There both gonna need heads cam intake carb headers cr etc.. Are the spec gonna be all that crazily different from one another?

Couldn't do 550 hp 340 around 7500 rpm with like a set of Trickflows or similar and Roller cam and the appropriate accessories ? How much less cam and head flow would a 440 take to make 550 hp and how much less a 540 take over that? Not like at some point with enough cid you could make 550 hp with stock 440 top end parts.

Here's a Honda k24 2.7l making 519 hp @ 9400 rpm with 435 cfm per cylinder 1740 total cfm which would be 218 cfm per cylinder for a V8, yes it's a crazy high rpm engine but doesn't need a crazy amount more total head flow to do it. To me shows it is a somewhat similar in it's needs to make similar hp within it's variables, Aka similar recipe.

https://www.motortrend.com/how-to/518-hp-4piston-racing-drag-spec-k24/
 
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The
273 said:
A 550 hp 440 is mainly consider mild cause it can spin less than 6000 rpms to make it.

There both gonna need heads cam intake carb headers cr etc.. Are the spec gonna be all that crazily different from one another?

Couldn't do 550 hp 340 around 7500 rpm with like a set of Trickflows or similar and Roller cam and the appropriate accessories ? How much less cam and head flow would a 440 take to make 550 hp and how much less a 540 take over that? Not like at some point with enough cid you could make 550 hp with stock 440 top end parts.

Here's a Honda k24 2.7l making 519 hp @ 9400 rpm with 435 cfm per cylinder 1740 total cfm which would be 218 cfm per cylinder for a V8, yes it's a crazy high rpm engine but doesn't need a crazy amount more total head flow to do it. To me shows it is a somewhat similar in it's needs to make similar hp within it's variables, Aka similar recipe.

https://www.motortrend.com/how-to/518-hp-4piston-racing-drag-spec-k24/
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There's a bunch of engines out there with higher specific output than our old dinosaurs.

Back to Mopar world, I think that, combo to combo, the barriers to a certain power level are gonna be lower if you're starting bigger. That's why I usually advise going with a stroker. If you can go big block instead of small block then yes do that. It'll make it all the easier to make big power.

Yeah you're generally gonna need heads cam intake and exhaust to get to 550, but particularly with the valvetrain and heads, the requirements are gonna be easier with the bigger engine. With a big block you're looking at something like a set of eddy heads and a decent flat tappet setup. With a sbm you're going to be investing a lot more to get there.
 
Mean416 said:
The

There's a bunch of engines out there with higher specific output than our old dinosaurs.
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That wasn't point, point was hp is gonna take similar air flow for similar level of build be it a 2.7l or a 440.

Mean416 said:
Back to Mopar world, I think that, combo to combo, the barriers to a certain power level are gonna be lower if you're starting bigger. That's why I usually advise going with a stroker. If you can go big block instead of small block then yes do that. It'll make it all the easier to make big power.

Yeah you're generally gonna need heads cam intake and exhaust to get to 550, but particularly with the valvetrain and heads, the requirements are gonna be easier with the bigger engine. With a big block you're looking at something like a set of eddy heads and a decent flat tappet setup. With a sbm you're going to be investing a lot more to get there.
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Don't think anyone has ever really argued the opposite.

I think people mostly agree on the advantages of displacement but I find a lot exaggerate the disadvantages of lesser displacements.
 
273 said:
Whatever is a reasonable rpm limit for a particular person/build.
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Then since the thread is moving away from stock 340 dyno build testing and your going into rpm based power, reasonable is indeed suited to the builder but you out a limitation on it and reasonable is out the window since the anti of the rpm is thrown out the window.

Let’s start with what rpm you think the 340 can obtain.
Shall we say 9500 rpm? Or should we go higher.
This is a interesting theoretical exercise.
 
I'm ok with laying rubber for a city block on the street...leaving a big stinky rubber smelling cloud behind as I leave...:)
 
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