69 340 Dart again...

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A Racer Brown ST-21 is [Email]254@0.050"[/Email] and 0.520 lift. That cam needs lots of lead, start with at least 20* of initial timing. The dual plane intake and 3.91 gear will help tremendously in getting it out of the hole.

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Mike,
The convertor seems a little tighter than 3500. I attributed that to the intake and cam not allowing it to make good torque. I hoped with the gear change it will loosen the convertor up by raising the RPM's.
If the convertor does truly work on torque...and this combo doesn't build much...if more torque was introduced wouldn't it stall a little higher?
That was the reasoning I used for an intake swap...
Originally I didn't want to do a gear change as I thought it was a band aid and I was just covering up the real fix.
I thought if I could make it run as good as possible with the 3.23's... then changed to the 3.91's it would be that much better.

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Your correct... more torque it will stall higher..
so yes if you can built more torque it will go up..
the gear is a torque multiplier also but thats after
the conv

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That cam really needs 4.56-4.88, and 4800-5000 converter, but I understand your choices. The only thing I could think is to try backing off on the total timing a couple degrees( 1 deg at a time). The LD-340 and 3.91's will help quite a bit.

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At Least 4.56.....what does the car weigh...????

My Challenger at 3200 lbs with 4.56 a similar 340 build (different cam) with worked X-Heads and a 750dp ran a best of 11.2 @ 117 in the 1/4....6700 at the stripe.

Rickster

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It's basically curb weight with the heater box removed and aluminum heads.
It had 4.56's in it for about a week. HATED IT And yes it does run much better.
I followed him back from a show about 60 mph for about 12 miles.
I could've brained him running it that hard.
He doesn't hear real well and must not pay any attention to the tach. I'm trying to nail down a better combo with whats there. He gets out on the interstate and runs 70-75 with it now with the 3.23's. I'll have a hard time breaking him of that with the 3.91's.
No one has really addressed changing the rockers from stock 1.5's to a 1.5-1.6 combination.
Wouldn't that technically make the cam seem bigger?

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It doesnt need more cam.. its too much right now but
with your changes it can help it... you need to look
at what that cam is installed at.. if you can advance
it 4*

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I bought a couple off set cam keys and a couple offset crank keys. When I tear the front off I wanted to have what I needed to put it back together after degree-ing it in.

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MP offers a offset key package.. can be bought from
Mancini's.... just in case you need more... see where
it is now but I would move it more.. even if its slightly
advanced now.. just check the V to P clearance
EDIT
I have moved a 108 lsa cam as far as 98* installed
but that killed my top end RPM... I had to back it
up to 101-102.. but at 98 it sure did have a bottom end
(torque)

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it sure did have a bottom end
(torque)

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Your exactly opposite where I am...
He likes the feel of the power...problem is where its at he's already speeding before he gets to feel it.
I'd like it to hit a lot harder and am willing to sacrifice some top end to get there.
Sounds like it needs advanced beyond recommended...

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I think a good convertor can make up for the 3.23's. HotRod did a torque convertor test years ago and it was suprising how well the highway gears would do with a good convertor. I think member Big Squeeze has a story where with a good convertor he was able to run very good times with 2.94 gears compared to a 4 something gear in the same car IIRC

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But he has a small list of things that will NOT be
changed and the conv was one