How do I find out how many spline my axels are? Is there a code that will tell me? Thank you.

 

Only way to tell for sure is to pull an axle out and count the splines on it.If you know for sure the rear has never been changed (it is original for car) you can narrow it down to what spline it MAY be for that year.What year is the car?Any detailed info will help any of us to better answer you.

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1982 Z28:355,4 Speed,Lots of bolt ons

 

I am pretty sure that after I think 87 all v8 cars had 28 spline axels.

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1991 Firebird
350 L98 (was a 305 TBI),T-5,Edelbrock TES and cat back,Accel manifold
NOS,subframes,jegster torque arm,MSD Digital 6
AFPR,Lakewood lcas
Hurst linelock,SLP cam (206 212 .480 .486),relocated battery,cold air,Hypertech chip,centerforce df,clutch
poly bushings and mounts
AFR 190s
Harland sharp 1.5 rockers
autopower rollbar

12.33 @ 114.83 juiced uncorrected

13.510 @ 102 non juiced uncorrected

 

It is an 89 RS 305 with 2.73 gears, original rearend.

 

89 is the crossover year. You should assume it's only 26 spline but the only way to know if it came off the assembly line after the change is to pull the axles and count them.

Up to 88 have 26 spline. 90 to present are 28 spline.