What rpm do you shift at?????
- Thread starter T67POWER
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pettybludart
Well-Known Member
I shift at 6000-6200rpm,engine is 410,solid roller cam(.631 lift 252,258)Eddy heads with mild P&P.My cars best run has been 10.81@124.55mph 60fts 1.50.I,m doing more work over the winter to get me in the lower 10,s We,ll see.:mrgreen:
340 8BBL
Well-Known Member
340.tunnel ram,dual 390 carbs,j heads,schneider custom hyd. 284 /234@50 /470 lift/112 lsa. i shift at 6000.
67Dart273
Well-Known Member
Asking this question of others is sorta like asking "how much money do you have?"
It's completely irrelevant, unless you had identical factory stockers or something.
The correct shift RPM could be quickly resolved my making a "full RPM run" in each gear on a graphing dyno. Your shift points are where the graphs crossover at each shift, and will not be the same RPM for each gear.
Of course there are variables, tire spin, reaction time, etc.
This is a poor chart, it doesn't show RPM, only torque versus speed
The idea is this. Start with first gear, and notice that the torque comes up, goes down, and crosses "2nd gear" coming on the way up. At the point where 2nd gear generates more torque than 1st, that is the shift point. That's where the first curve (dark blue) on the left meets the pink curve at about 33mph
Unfortunately the chart needs to be in RPM not speed.
It's completely irrelevant, unless you had identical factory stockers or something.
The correct shift RPM could be quickly resolved my making a "full RPM run" in each gear on a graphing dyno. Your shift points are where the graphs crossover at each shift, and will not be the same RPM for each gear.
Of course there are variables, tire spin, reaction time, etc.
This is a poor chart, it doesn't show RPM, only torque versus speed
The idea is this. Start with first gear, and notice that the torque comes up, goes down, and crosses "2nd gear" coming on the way up. At the point where 2nd gear generates more torque than 1st, that is the shift point. That's where the first curve (dark blue) on the left meets the pink curve at about 33mph
Unfortunately the chart needs to be in RPM not speed.
T67POWER
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67dart273................
Shift points don't have as much to do with the amount of money spent as you might think.
I have seen some very high performance engines shift at lower rpm's.
I might shift my 360 higher then the next guys stroker emgine.
It really depends on the engine.
The theory you have, does not always work the way you would think.
The weight of the car and it's gearing has a lot to do with your shift points.
Have you tried the theory at the track yourself????
Shift points don't have as much to do with the amount of money spent as you might think.
I have seen some very high performance engines shift at lower rpm's.
I might shift my 360 higher then the next guys stroker emgine.
It really depends on the engine.
The theory you have, does not always work the way you would think.
The weight of the car and it's gearing has a lot to do with your shift points.
Have you tried the theory at the track yourself????
1968FormulaS340
Well-Known Member
What he posted is not a theory. It's called staying on top of the curve. It is the science of going fast.
about 7000 rpm 345cui ported edelbrockheads 242/248 @ 050 solidroller same basic engine will soon be out on the street again with a twinscrew supercharger 
used to shift 345cui at 7500 with a 260 @ 050 solidroller with ported J heads
used to shift 345cui at 7500 with a 260 @ 050 solidroller with ported J heads
If you don't have access to a chassis dyno, on the track, you can vary your shift points on each run and compare your time slips to see where it performs the best and once you have the data on paper, it's not too hard to compare. Same goes for making changes to the car. Even something small like a timing change can make a difference in a shift point. If you do have chassis dynos in your area, go to the same one each time you go. They are a good tool but it's still not the same as 'real' time on the track.
longarm
Car sold back to original owners
If you or a friends can get your hands
on a Gmeter try that.
They are fairly common.
You can build a crude one and use your memory tach
to record shift points or have your pard record for you.
Google: diy g force meter
on a Gmeter try that.
They are fairly common.
You can build a crude one and use your memory tach
to record shift points or have your pard record for you.
Google: diy g force meter
moper
Well-Known Member
Yup. The easiest way to get your own best is to first, get the car so it's repeatable to the tenth of a second. Then make runs varying the shift point by 200 rpm each run. I start with the 2/3 in the auto or 3/4 w/ a 4sp shifts. Then when you've gone as fast as you can, work on the next lower gear. It seems easier that way but normally you can find at least .1-.2 more just by doing that. Some really poor drivers will find much more (because it's the driver that times shifts poorly, not the package). I'l also add, the shifts are usally a lower rpm than most might expect.
DieWilde13
Well-Known Member
I shift at around 6000+ rpm. With a 340 Engine the Fun beginns at 4500 8):cheers:
darndart
Well-Known Member
My old 10.5:1 340 with MP 557 cam, Ported J heads, M1 single plane, I shifted at 6200. I tried higher, all the way up to 6800, but it didn't help my ET, so I stayed at 6200!
1968FormulaS340
Well-Known Member
Exactly. Shift point is very build dependent. My combo wanted a 7800/8000 shift point and that is where it got it's best ET.
If I shifted at 6200 I would be keeping the car way under the curve for the entire run and my ET would have suffered.
dodgetkboy78
EDELBROCK HEADS SUCK!
359 Cubic inches, around 1500/1500/1500/1700/1800/2000/2400/2500/ if I am in a hurry pulling a 15K trailer........ HHAHAHAHAAAAA
390, 302 heads, 5600/5200. (74 one ton)
318, roller valetrain, X heads, 7400/7100 (My old 74 Duster)
273 2bbl, 5000/4800 (Wife's 88 ramcharger)
I always shift higher than the curve in the lower gears to be farther into the curve in the upper gears...... (Just me)
390, 302 heads, 5600/5200. (74 one ton)
318, roller valetrain, X heads, 7400/7100 (My old 74 Duster)
273 2bbl, 5000/4800 (Wife's 88 ramcharger)
I always shift higher than the curve in the lower gears to be farther into the curve in the upper gears...... (Just me)
green1
Well-Known Member
Sit down and look at cam specs, head flow, carb; then calculate rpm for best shift.
longarm
Car sold back to original owners
Or you could just buy or build a G meter and see when
you combo was running out of steam and shift at that point.
you combo was running out of steam and shift at that point.
Hell, just shift when the valves float. That's the best chip there is.
67Dart273
Well-Known Member
This is "sorta" close to what I posted, but you can't just "shift when it runs out of steam.
What you would have to do is, graph G readings in each gear, then shift when the "G" points cross in each gear
dont try this with a roller...
i have seen my tach jump past 8000 without a chip and without any valvefloat that i could hear when i blew a inputshaft,just cost me a pushrod just happy my stockrods swinging heavy TRW pistons did not chose to make a nice set of windows in the block.
dodgetkboy78
EDELBROCK HEADS SUCK!
It is amazing what stock rods and TRW's can spin................
yep they are probably alot better compared to alot of the new cheap rods being made today. and i think those old 340 rods may have been put thru alot harder tests in the past with heavy pistons back when there wasnt much more to chose from
The small block Mopar is just amazaing. PERIOD. A work of art one could say.
/6 Matt
30 Degrees Crooked
5K WOT with a bone stock slant.
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