Would a 91 z28 700r4 be a direct replacement for my 700r4 (stock) thats in my 87 iroc with 350 motor?

 

There's a speedo gear inside that may be different (super easy to swap by unbolting the tailhousing) and you'll re-use your driven speedo gear parts instead of the 91 VSS. Other than that, 100% straightforward swap.

 

Got it

Thanks for the info

 

the 87 trans in you camaro has a mechanical (cable driven) speed sensor, the 91 has an electric one. I "think" the sender will fit either trans, but IDK about the drive/driven gears.

 

Every third gen was built with a speedo drive gear on the output shaft. Including TTA, Firehawk, models with mech. speedo and models with VSS at the trans.

The mech. speedo ones have a speedo driven gear.
The VSS models have a speedo driven gear on the VSS.

The reluctor ring and magnetic pickup VSS was never installed in third gens from the factory.

So for the OP, it's the same style drive gear on the ouput shaft and it only needs changed if it's a different tooth count.