valve tool? lifter lifter?

[skipskip]

Came from older Chevy dealer.

No brand or numbers do I see.

Whatsit?

[john k]

I will say I've never seen a device like this.  But by removing the stamped rocker arm, looks like it could compress the valve spring by pulling on that long extendable handle.  On the old Chevy V8. 

[Carl]

Not a lifter tool. It looks like it releases an internal retainer.

[rusty]

Speculating it is a transmission shaft release tool....

[amecks]

It certainly resembles a tool used to compress tappet springs in a diesel fuel injection pump. The slotted part would connect to a bolt on the pump bottom, the pivoted piece would force the tappet against the spring (as you push on the handle) and you would insert a pin to hold the tappet in position. With the tappets "up" the pump camshaft can be moved into place.
Like I said it closely resembles such a tool - not sure if that's what we have here. Al.