thunderize

Can someone tell me how I can tell what gear I have? I have a 66 coupe with a 289, C4.

THUMPIN455

you can find out rather easily. Ther eis a tag on it that will tell you, unless its been removed or changed.
There is another tag on the drivers door that should have what the car was originally built with.
Also you can lift the rear of the car, put it on jackstands, place the shifter in neutral. Now you can rotate the wheel so the valve stem goes around one complete revolution. Count how many times the driveshaft goes around.

if the driveshaft spins 3 times, its 3.00:1, if it spins a bit more than 4 times, its a 4.10 or more gear. If it doesnt quite spin 3 times then its under 3.. you can sorta guess at the ratio from how far it spins past each whole number.

If you car is stock and unchanged, it will usually have a 2.70 or a 3.00 rear end in it.

Soaring

99% chance it is a 280 open.

thunderize

Thanks everyone i found it today. I bought a restoration book that explains the I.D. #. It is a 2.80