Decoding Questions

Discussion in '1977 Z28' started by TruckDoc, Mar 22, 2019.

  1. TruckDoc

    TruckDoc New Member

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    Update, Found stamping numbers in axle tube, Makes it a PWG 70751 which should be a 3.08 locking. Cover comes off tomorrow evening. Engine that should be in it more or less should have been a 350 LM1 (CKS) but there is three listed and by model year would have been matted to an automatic at a meager 180hp. The trans in the car is a Saginaw 4spd with a 3 groove 10 spline input shaft. When looking this up without taking unit apart comes back as a 3.50 first gear. I can't seem to nail down everything about the trans. The stamped number below the side cover reads R1M07 which should decode to a 4spd built in August of 77? but trim tag puts car build March 77. So along with the engine I am going to assume its not the original one either. Any help guys would be greatly appreciated. This is my first Car build and I want as much info going in as I can possibly get before I start to order hard parts. The Motor I will leave alone, Its a stroked 400 and is very healthy(Scary)
     
  2. Gary S

    Gary S Administrator Lifetime Gold Member

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    The tranny number R1M07 decodes like this.
    R=Saginaw
    1=1971 or 1981
    M=August
    07=day 7 of month
     
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  3. TruckDoc

    TruckDoc New Member

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    That makes more sense. I am still having trouble reading the code info out. Give me a semi truck, no problem LOL
     

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