Get me into the 11s

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Tool505

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Trying to get into the 11s with my 74 dart. Build list is below. Had it on the dyno without spray last month having carb issues ( ran super rich on top end not responding to jet changes ) and it only put 350 to the wheel, few pulls later it spun a rod bearing. Engine is back together and I'm hoping that number will climb later this week with a new carb before the spray goes on. Do you think my build can hit 11s or where am I lacking. Running at Colorado altitude.

408 stroker magnum block
Eq heads 1.92 and 1.60
10.5 to 1
Forged Pistons, rods and crank
Air gap manifold
800cfm Holley double pumper
Full length headers and 2.5" back
3.91 rear end
3speed a230 trans
26x8.5 slicks
Aeromotive street strip electric fuel system with return to sumped tank
Dedicated 1 g fuel cell and pump for plated nitrous system ( planning on 150-200 shot )
Don't have cam specs handy but it's a Howard's hydraulic roller not too aggressive.
 
What's the car weigh?
What actual altitude? Colorado is all over the map.

350 horse at the wheels is enough for very low 12's in the average a body (3400 pounds with driver). A 100 shot ontop of that would more than put you into the 11's.

Cam specs would be nice too.
 
Lustle said:
What's the car weigh?
What actual altitude? Colorado is all over the map.

350 horse at the wheels is enough for very low 12's in the average a body (3400 pounds with driver). A 100 shot ontop of that would more than put you into the 11's.

Cam specs would be nice too.
Click to expand...

3400 pounds should be a safe bet ( haven't weight it yet ) elevation is 5800'
 
So 350 horse at the wheels at that elevation?

Assuming you're actually 3400 pounds. And can actually put that 350 horse down. That's 12.10's. A hundred shot of nitrous will more than put you into the 11's.
 
What is your 60 ft, 1/8 and 1/4 numbers? Is your compression ratio optimized for your altitude? I don't know much about that, other than you only have 80 percent(roughly) of the air at sea level. Just sorting out your fuel curve will help a lot. How much true stall do you have, assuming this is an auto trans?
Have you had the heads flow tested? Any bowl porting, or port work done? There is a lot of power there if you haven't. The EQ heads pick up a lot of flow with work, and you have a lot of cubes to feed.
 
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If it's an uncorrected number you should be good ad close with a decent leaving car.
 
What rev ranges are you running with that A230 3 speed manual? I'm just curious as to how well that is matching with your cam RPM range...
 
A 3 speed manual transmission might be the worst possible choice in that car....
 
I kinda figured it would be worth asking about for that reason....cam specs or PN would be VERY helpful.
 
Oh IDK, the A230 and 3.91s are a pretty good deal I thought.
3.91s are a little short but hey, it's a 408 not a weak-kneed 340.
But I know what you mean, the engine is gonna need a very wide powerband to pull those splits.
But a 350hp 408 cuber kindof points to that.

3400/350+100=7.55pounds/hp and that might get you 120mph. That maths out to about 6100rpm
I just can't remember the ratios in that A230 but I'll guess at 2.95-1.60-1.00. The splits on that would be 54 and 62.5. That sounds pretty close. If the power peak was 5800, then the shift rpm might be up near 7000, to drop in at 3780 into second and into third at 4380. So the powerband would need to be strong from at least 4200ish to 7000, or 2800rpm. If the power drops off too fast by 7000, then short shifting will drop the bottom into the basement.
>Say the power is rolling off rapidly after 6600, and there is no point in continuing. Then those same splits of 54% and 62.5%, will make the drop-ins at 3564 and 4125. This is well below the torque peak at perhaps 4350. The power band now needs to be from 3850 to 6600, or about 2756 rpm.
> So no matter how you look at it, That 408 is gonna have a long hard slog. Thank goodness for nitrous.
Getting back to 120mph; this is about 11.1 seconds with unlimited suspension. Or perhaps as little as 11.6ish with street suspension. So, just crank up the boost til you hit your target,lol.

A 4speed would indeed make it easier.The powerband requirement of those, in this application, is about 1800rpm. But the starter gear will suffer; 3.91 x 2.66=10.40for the A833 vs 2.95 x3.91=11.53 for the A230. To match that 11.53 will require a swap to 4.30s imagine that. And the Rs at 120 with 4.30s will be about 6670. This will then want the power peak moved up to 6200 or better, about 2 or 3 cam sizes. Of course to make best use of that new cam, the compression would like to be increased too. Or just pump some more nitrous into it,lol.
Oh boy, what did I get myself into................
 
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I'll see if I can get the cam specs. Right now she feels pretty wrapped out at 6k. Dropped her off to get tuned tonight I will report back tomorrow hopefully. It is stock suspension right now
 
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