327/powerglide RPM question
03-16-2017, 06:23 PM
#1
327/powerglide RPM question
my '67 had a TH350 installed. at 70 mph, my tach reads 2,700 rpms. can somebody tell me what their tach reads with a 327/300hp/powergilde at 70 mph? just curious what the difference is.
03-16-2017, 07:07 PM
#2
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a TH350 and a powerglide both have a finale gear ratio of 1:1. so both would be the same. rear gears is how you lower the RPM or a overdrive trans
03-17-2017, 10:18 AM
#3
03-17-2017, 12:02 PM
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03-17-2017, 03:19 PM
#5
Burning Brakes
Since I don't believe either of these autos has the "lock-up" converter of more modern transmissions, is there any slippage in either of these at cruise? I guess my question is, is there a true 1:1 ratio between the engine and transmission output ? 
03-17-2017, 04:18 PM
#6
I have 215 70 -R with all Powerglids have 336:1 In owners manual
I was going to go 70 MPH and let him know what my RPM was he should be able to see difference Right.
Last edited by rtruman; 03-17-2017 at 04:19 PM.
03-17-2017, 04:31 PM
#7
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St. Jude Donor '07
i'm with Nowhere Man on this, without having the same RER (and diameter tires...) it's apples & oranges; no comparison.....
Bill
Bill
Last edited by wmf62; 03-17-2017 at 04:32 PM.
03-17-2017, 04:36 PM
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03-17-2017, 04:39 PM
#9
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Same 1:1 as a Muncie or 3 speed or any other trans that's not a overdrive
03-17-2017, 04:39 PM
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St. Jude Donor '07
all other things being equal, any rpm difference between his TH350 and the powerglide would be due to the torque converter.Bill
Last edited by wmf62; 03-17-2017 at 05:03 PM.
03-17-2017, 04:43 PM
#11
I know a power glide will go as fast backwards as forwards .
03-17-2017, 05:19 PM
#12
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'66 coupe with 327/300 and powerglide with 3.36 and positraction. At 2700 my speedometer reads 70mph, but found that my speedometer at 70mph shows 63mph via GPS. Anyone making mph/rpm claims should first check their speedometer for accuracy. Found out that I had an inaccurate speedometer.
03-17-2017, 06:20 PM
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03-17-2017, 07:12 PM
#15
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Not with a non-lockup, non-overdrive automatic. Typically, converter slip will raise RPM 300-400 over an identically equipped stickshift car.
03-17-2017, 08:47 PM
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03-17-2017, 09:59 PM
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