High revving 340 stroker questions

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MOPARCODY

MOPARCODY

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I have an inquiry in with an engine builder. We’re meeting next weekend to talk about options but I’m being inpatient so I figured I’d ask a few questions on here.

I’m interested in building a 340 stroker. If like to run low 10s on motor but also be capable to run a moderate sized shot of nitrous for grudge type events.

my builder mentioned that he likes to build higher revving engines with shorter ish stroke cranks.

does anyone have any experience with the higher revving small blocks and why he would recommend that?
 
I don't know your set up but everything needs to be right for low 10's. Scott (pettybludart) has a 408 in his 66 Dart. It's pretty light and a purposely built race car. The 6.65 converts to 10.37 1/4 mile time. Build the stroker. Look at the cars and times in 70aarcuda's signature line above. The 408 tells the story. Scott has been running this same combination for years. It just works!

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MOPARCODY said:
I have an inquiry in with an engine builder. We’re meeting next weekend to talk about options but I’m being inpatient so I figured I’d ask a few questions on here.

I’m interested in building a 340 stroker. If like to run low 10s on motor but also be capable to run a moderate sized shot of nitrous for grudge type events.

my builder mentioned that he likes to build higher revving engines with shorter ish stroke cranks.

does anyone have any experience with the higher revving small blocks and why he would recommend that?
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RPM cost money, it cost's money to build for it and it cost's money when it breaks. It is always much better if you can achieve your power goals at the lowest RPM possible; it's called less stress!
 
We need more information. The weight of the car, tires , transmission, rear end, & other such stuff. My Demon weighs in at 2500 lbs, 408 stroker. 727 RMVB trans, Dana 60. 4.88 gears, 29.5 x 10.5 C06 Hoosier radial slicks, runs tens all day long. Building a 416/904 with hopes of going 9's.
 
MOPARCODY said:
I have an inquiry in with an engine builder. We’re meeting next weekend to talk about options but I’m being inpatient so I figured I’d ask a few questions on here.

I’m interested in building a 340 stroker. If like to run low 10s on motor but also be capable to run a moderate sized shot of nitrous for grudge type events.

my builder mentioned that he likes to build higher revving engines with shorter ish stroke cranks.

does anyone have any experience with the higher revving small blocks and why he would recommend that?
Click to expand...


I like your engine builder. But everyone has their own definition of high RPM so you need to clarify what he means.

FWIW I consider anything under 8000 is street RPM.
 
Demonracer said:
We need more information. The weight of the car, tires , transmission, rear end, & other such stuff. My Demon weighs in at 2500 lbs, 408 stroker. 727 RMVB trans, Dana 60. 4.88 gears, 29.5 x 10.5 C06 Hoosier radial slicks, runs tens all day long. Building a 416/904 with hopes of going 9's.
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72 duster, 2900 lbs, 28x10.5, 8 3/4 391 mvb 904. Has a 360 crate motor in it now. I know I’ll have to change rear gear and build trans
 
If you build a 4.070 bore, 3.79 stoke that is 395 inches. You can use a 6.250 chevy rod and a 4 inch stroke piston and go. Use enough head and cam to shift at 7500.
 
yellow rose said:
I like your engine builder. But everyone has their own definition of high RPM so you need to clarify what he means.

FWIW I consider anything under 8000 is street RPM.
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So you consider 8000 on the "low" side even though it requires oiling and valvetrain mods? I have a tough time imagining an engine that revs to 8 grand and still has decent off-idle torque and street manners below 3000 RPM unless it's built with some exotic hardware? Honest questions...
 
If you use off the shelf parts...like a 4 inch crank...6.123 rods..and 1.466 ch pistons which all are available in a kit...you will be time and money ahead...and not have one of one...
going to need an 8 inch converter more gearing...and hope your 8 3/4 hangs with you...
 
High rev and stroker are kinda opposites. What most people build strokers for on the street is for gobs of bottom end torque. Sure, there are exceptions, but that's it for the most part.
 
you defiantly don't need a stroker to run low 10's.
my car is 2900 lbs. stock 360 crank and rods.
10.20 @ 130 mph. 6.44 @ 106 mph 1/8
 
a friend campaigned a 372 with 280ish cam, edelbrock heads and something like a 4.56 gear in a '71 duster that ran low tens. I think he said he shifted around 7800.

...now that i think about it,i'm pretty sure he ran 4.88 rear gears
 
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I would build a B Block 400 stoker to 512 . Revs like a small block, and pulls like a big block..
 
MopaR&D said:
So you consider 8000 on the "low" side even though it requires oiling and valvetrain mods? I have a tough time imagining an engine that revs to 8 grand and still has decent off-idle torque and street manners below 3000 RPM unless it's built with some exotic hardware? Honest questions...
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You have to do some mods, most of which I do regardless of RPM.

If the engine is right, the bottom of the torque curve will fill itself in nicely. Street manners are largely getting the correct parts and TUNING. Tuning is a huge deal.
 
Unless you’re using some fairly exotic top end components....... you can usually figure that the tq peak and the hp peak will end up about 13-1700 apart........ a nominal 1500rpm spread.
(That’s if the heads are adequately sized to “keep up” at high rpm.
Often times, especially if the cam is big and the heads are small, the peaks can end up more like 1000-1300 rpm apart.)

So if you’re building to make peak power at 7k..... peak tq will end up around 5500.
So, you’d end up with 5500-6000 stall if you were going after the best ET.
This type of powerband would generally be geared to turn around 7500 thru the lights.

Imo, that type of combo isn’t really much fun to “drive around” on the street, plus you’re just wearing parts out.
If it’s basically just a race car....... no problem.
 
B block balanced 440 Source 512 Stroker Kit, Trick Flow 270 Max Wedge heads, Indy Max Wedge single plane intake, Comp Cams 1.5 roller rockers, Comp Cams .650 lift solid lifter cam, out of the box Quick Fuel 850cfm Q series carburetor....and a Wilson 2” tapered 4 hole spacer. PUMP GAS!!!! OK, We used 91 octane pump gas with less than 10 percent race gas for testing. Plan to use 93 octane for “daily” driving
 
Not sure it’s not my engine, reach out to the folks in the video
 
toolmanmike said:
I don't know your set up but everything needs to be right for low 10's. Scott (pettybludart) has a 408 in his 66 Dart. It's pretty light and a purposely built race car. The 6.65 converts to 10.37 1/4 mile time. Build the stroker. Look at the cars and times in 70aarcuda's signature line above. The 408 tells the story. Scott has been running this same combination for years. It just works!

View attachment 1715662993

View attachment 1715662994
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Is Scott even on here anymore? Kim
 
416 cu in 8000 rpms+ car weighed 3850 10.60's at 128. 5500 stall 456 gears 28" tires. car was heavy. 6 yrs of beating and it still lives. Through the exhaust with the tips

 
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The thing is do you want a "race car" or a "street car "? they are 2 different animals. The street car should be built for long term durability. Like the difference between a NASCAR engine that must live for 500 miles or a drag engine that onlky has to last a few seconds. Different requirements, different builds. High lift cams, low spring life, Worn springs, lower rpms and on...
A 360 is a bored and stroked 318 but with a stronger bottom end block. A 340 is an overbored 318.
 
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