Identify my motor please

[DanB4]

So, I know it's a Trinity Monster Horsepower, but it has a machined endbell, nicely machined actually and a shiney can too.....the box has "Trinity test motor" hand written on it and the motor looks to be very lightly used if at all - I assume it has been used as has motor wires fitted.

Any ideas guys? Is it a modified (says so on the box!)? I could open it if necessary.

Dan