Tach Problem
Thread Starter
Junior Member
Joined: Jan 2001
Posts: 79
Likes: 6
From: Belleville MI
Car: Formula
Engine: Pontiac 400
Transmission: T56
Axle/Gears: 4.10
Tach Problem
89 RS Conv, 305, 700R4/4L60 3.08 Stock gears.
Mods: Converted to Carb From TBI, 600 Holly, Edelbrock Performer RPM Intake, 85 HO heads, Accel HEI Coil with HEI Distributer off of an 86 T/A (i think) Hedman Hedders and Y-pipe, hollow cat.
Problem: Tach is telling me at 70 mph i'm running 4000 RPM in .70 4th Gear with 3.08 and a 26.58 inch diameter tires.
Possibly bad tach? Any help on how to check or fix would help.
Drove it like i stole it and had to buy another one.
Mods: Converted to Carb From TBI, 600 Holly, Edelbrock Performer RPM Intake, 85 HO heads, Accel HEI Coil with HEI Distributer off of an 86 T/A (i think) Hedman Hedders and Y-pipe, hollow cat.
Problem: Tach is telling me at 70 mph i'm running 4000 RPM in .70 4th Gear with 3.08 and a 26.58 inch diameter tires.
Possibly bad tach? Any help on how to check or fix would help.
Drove it like i stole it and had to buy another one.
Supreme Member
Joined: Jan 2001
Posts: 7,604
Likes: 1
From: ****SoCal, USA****
All I can tell ya is that you are almost doublng the signal to your tach.
For my 1974 Corvette with 3:08 & TH400 tranny,
I'm pushing about 100 MPH at 4k on the tach.
On my Corvette tach, 70 is about 3K. But again, I DO NOT HAVE OVERDRIVE.
------------------
Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA
For my 1974 Corvette with 3:08 & TH400 tranny,
I'm pushing about 100 MPH at 4k on the tach.
On my Corvette tach, 70 is about 3K. But again, I DO NOT HAVE OVERDRIVE.
------------------
Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA
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