New life for an old 340 (stock stroke)

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MOPAROFFICIAL said:
Nice job, Different animal.
What did the heads do?
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Pump gas 383 with ported 346 heads(275-280-ish), 750 carb, 1-7/8” headers.

Nice numbers out of Ramm’s 340 though.

My old 340, which was a pretty similar build made 412tq/478hp, but had a bigger cam in it.
 
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Thats a nice 340 for sure and nice to see an engine that has a longer usable powerrange than all those underheaded oversized strokers we see so often nowadays.
For what its worth imho,big part of the short numerical spread between peaks often seen is due to the underheaded oversized strokers so popular today,and that is not to take anything away from this build,this seems like a very nice build.
 
Nice job! I’ll have to dig out my 340 dyno sheets and see how theses match up, looks like you made about 17hp more than mine
 
Dwayne chose the cam for my 434 small block and peak torque is at 5000, peak hp at 6750.
 
I do have a few questions on the 650 carb, since I run a demon 650dp on my 340.
It was 74 square jetted?
Are you using any power valves?
Downleg or annular boosters?
1:1 or progressive secondary linkage?
Thanks for any additional info.
 
PRH said:
110lsa, off the shelf cam, dual plane manifold......2400rpm between peaks.
Would need to know the whole combo to understand this one because I have seen in certain situations a really large spread and lower than expected peaks points to one piece of the puzzle being really out of wack effectively hamstringing peak torque/hp production.
View attachment 1715271431

115lsa....... 1700rpm between peaks


View attachment 1715271439

Imo, there’s no magic in the lsa. It’s about the whole combo.
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Not saying there is any magic in the LSA but I am saying I like to use it to get what I want.
Also saying it is not always wise to go to a narrow one especially in the case of these 4" crank with OEM heads deals.
I do agree with you however--the whole combo. J.Rob
 
1Fast340 said:
Thats a nice 340 for sure and nice to see an engine that has a longer usable powerrange than all those underheaded oversized strokers we see so often nowadays.
For what its worth imho,big part of the short numerical spread between peaks often seen is due to the underheaded oversized strokers so popular today,and that is not to take anything away from this build,this seems like a very nice build.
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Totally agree with your statement--the typical underheaded 4" stroker is finished before 6000 rpm and while that may be just great for some, it would not be an engine I would particularly be satisfied with. I wanted to build a 340 worthy of the legendary status they have due to their eagerness to RPM--that is not a 4" arm with X heads. J.Rob
 
mderoy340 said:
I do have a few questions on the 650 carb, since I run a demon 650dp on my 340. This is an XP , the emulsion package could be different , which changes jetting req
It was 74 square jetted? Yes
Are you using any power valves? Yes
Downleg or annular boosters? Downleg, annular don't exist in a venturi this small off the shelf
1:1 or progressive secondary linkage? Progressive but that won't matter on a dyno
Thanks for any additional info.
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You're welcome, J.Rob
 
rumblefish360 said:
Nice! Those mildly ported heads helped carry the mechanical cam a bit further than stock heads would by miles! I think the low amount of porting did a great job. How did it do under the posted test rpm? Is there an example around 3K done?

I know the small single plane doesn’t take so well that low.
Just wondering.
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I only tested as low as 3500 rpm where 375-380 tq was observed. It loaded real nice and strong and didn't fall on its face coming off the brake. I'm starting to gain some respect for the old Torker 2. J.Rob
 
Would need to know the whole combo to understand this one because I have seen in certain situations a really large spread and lower than expected peaks points to one piece of the puzzle being really out of wack effectively hamstringing peak torque/hp production.
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No magic in that combo, but it did make a bit more top end power than I expected.
About 10:1, like I said already.....ported 346’s, RPM intake, ootb hp750, 1-7/8 Hookers, stock crank and rods, milodon pan and tray, Comp xs282s with the older blue 1.6 Hughes rockers.

I wonder if you took that same cam you had done for the 340, ground it on a 108 instead, installed it with the same amount of advance as you did the 113 cam..... changed nothing but the lsa...... what the difference in peak power(tq and hp) would be, how much the tq and hp spread difference would change....... and which one would show a better “score” under the EM scoring criteria.
Somewhat of a proof of concept test.

When that was done several years ago with a sbc, the tighter lsa was the winner on that build.

Not to totally highjack the thread.......
It depends on what you’re doing as to whether a 14-1600rpm spread is an issue or not.
In a drag car, thats plenty.

When I had the 448 in my car, the on track operating range was 1500rpm(5300 stall, 6800 at the finish line, and the 383 was 14-1600rpm(5400 stall, 6800-7000 at the finish depending on the weather).
My 383......stock 400 cast crank, stock rods, TRW L2315’s with flycuts, unported 906’s, rpm intake, hooker 1-7/8”, ported 850 carb...... peak tq at 4300, peak hp 6200(1900rpm spread)......106lsa cam in at 102.

The other day I posted a dyno sheet for a bracket race 416 with bowl ported rpms and a solid cam...... 106lsa, in at 102...... 1600rpm spread.

918hp 14:1 572 with cnc 572-13 heads and a .825 lift cam on a 112...... 1200rpm spread.
833@165 @2750lbs
 
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RAMM said:
I wanted to build a 340 worthy of the legendary status they have due to their eagerness to RPM
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As we can see from the dyno sheet the engine is not done yet at 6900RPM since power is still climbing... did you take it any higher than 7000 to see what the power curve would do? Or not worth it for a measly 2Hp more and more stress on all parts?
 
stixx said:
As we can see from the dyno sheet the engine is not done yet at 6900RPM since power is still climbing... did you take it any higher than 7000 to see what the power curve would do? Or not worth it for a measly 2Hp more and more stress on all parts?
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I turned it higher and it was down 4 hp @ 7000 as it heads downwards gradually. J.Rob
 
RAMM said:
Not saying there is any magic in the LSA but I am saying I like to use it to get what I want.
Also saying it is not always wise to go to a narrow one especially in the case of these 4" crank with OEM heads deals.
I do agree with you however--the whole combo. J.Rob
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IMHO... points to knowing the application needs first and then combining parts to get what you want. Big breathing and smaller, wide LSA is gonna compromise peak HP but is gonna spread the usable torque band. In some uses, where you never can put big peak HP to the ground, and don't have a 10 speed transmission, this is the best outcome. So there is no one 'best formula', just the best for application ABC....
 
Nice engine build and solid runner. Good job!

I'd slap that in a street car A body and go run 11's.
 
This, as with pretty much any thread RAMM posts, has been quite educational and keeps ideas moving in my head.
 
Close...

3F592EB6-A6C1-4A40-BFD3-D72D9DA76C68.jpeg
 
rumblefish360 said:
Nice! Those mildly ported heads helped carry the mechanical cam a bit further than stock heads would by miles! I think the low amount of porting did a great job. How did it do under the posted test rpm? Is there an example around 3K done?

I know the small single plane doesn’t take so well that low.
Just wondering.
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Look at the tq drop off point...If you were shifting that motor it would be earlier than the hp peak rpm , or feel wrung out with the tq dropoff. Also has an electric water pump on it freeing up that top end .
This is a great build and imo more like 445-455hp motor which is still very respectable. I'm sure if it had a hair more squeeze it would tolerate less timing and vice versa. 30 or 32 or 34 is not a surprise with a small block mopar.
I had forgot about this thread, might have already gave my observation. Still cool stuff.
 
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