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Gearing issue?
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TOPIC: Gearing issue?
#1522
Gearing issue? 2 Months ago  
Hi all...

I have a 1967 2+2 with a 428 and 4 speed. The rear end is a 3.55 posi-trac. The car has a tri-power set up, not the stock 4 bbl. Here is my issue, at 55-60 mph the hood tach has me at 4000rpm. That seems way too high, but more troublesome is that it blows through the gearbox way too fast... meaning, I can barely get the tri-power opened up before I need to shift. And the shift come really fast as the tach spins quick up the redline... but, I don't feel like I am getting full power to the ground before I shift.

For reference, I have a 71 GTO with a 428 and 4 speed and it winds up nice in the power band before each shift occurs. So, I have some familiarity with a 428 and 4 speed combo.

Any suggestions or ideas? Is the rear end too steep? My dad wants to enjoy this car when I am in the GTO and he would prefer more of a cruiser than a stoplight to stoplight beast...

Thank you for any and all suggestions and input...

~ Chris
Missoulaman73
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#1523
Re: Gearing issue? 2 Months ago  
Chris -
Welcome to the Registry!
Something is not adding up. My 4-speed 2+2 has a 3.42 rear. The tach reads 3100rpm @75mph. My Corvette has a 3.70 rear and is doing 80mph @ 4000rpm.
Your tachometer is not reading correctly. Get it checked.
In the meantime, try ignoring the tach and shift by ear.
BTW, your car used to belong to Registry member Steve Surgeont in Florida (now deceased).
OldInjun
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#1525
Re: Gearing issue? 1 Month, 4 Weeks ago  
Thank you Jack...

I have driven it by "ear" and when I do it is really awesome... but, pretty scary to see the tach hit 7000 rpm too... but, the motor has not exploded yet... so maybe that is more where I need to look for my gremlins.

How would I go about getting the tach checked or getting a more accurate rpm reading? There is no OBDII port to plug into... Lol...

Thanks again.

~ Chris
Missoulaman73
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#1526
Re: Gearing issue? 1 Month, 3 Weeks ago  
You probably need to send your current tach out for repair.
I would invest a few bucks in a cheap tach, hook it up to the coil (negative side) and a ground with some lead wires, and see what it reads before doing anything else, though.

Jack
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