More than likely you have 2:73 gears. The easiest way to check but not perfectly accurate. If you have an auto put it in D. Get up to 70mph. Say your tach reads 2730 rpms, then you have 2:73 gears and so on. The gear ratio affects many things. The lower the gear ratio numerically the higher the gear you have and vice versa. If you want mpg and top speed you'll want to keep your stock set up more than likely. But if you want increased acceleration, and don't mind decreasing your top speed a little then you might want a lower gear like 3:42s.
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"Putting any amount of money into a RICE BURNER is like wiping your a$$ with a turd. "
'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
3" Hooker CatBack w/Aero Chamber muffler
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat, just switched to 180* b/c of winter coming and going to college in the mts.
3:73 Posi
Rebuilt 700R4
B&M Megashifter, 5" Autometer Tach w/shift lite | 
