[RRF]

It is the original turbo 350 that came with the '81 4.9L Turbo engine.

I read somewhere the turbo 350's that came with the 4.9L turbo engines were a "heavy-duty" version to handle the increased torque load of the turbo-charged engines.

The car will just break loose from a stop (3.08 gears) and a bit of "chirp" is normal on the 1st to 2nd shift, but at top end, the engine seems like a lot of power is not getting to the pavement.

I read somewhere else that low top end was an indicator of a poor torque convertor.

But how can you really tell, other than replacing it?