stepper motor suggestions

I have a collection of 8 stepper motors 4 of them are the same and the other 4 are all different.They are all NEMA 23 housings. The other 4 motors are Superior Electric Slo-Syn steppers that have a fairly high amperage listed on the back of the housings (4.7 amps/phase) so I suspect they might be too big for this shield.

The 4 that are the same have 6 wires they have no data sheets available on the net so I ohmed them out and had found what would be the center taps (2) and the others I separated into into 2 pairs that designated for coils A and B.

I am fairly sure that I have grbl in my arduino now because when I open the arduino serial monitor window it has returned–> “Grbl 0.6b ‘$’ to dump current settings”

Then when I type in “$” it returns—->

$0 = 755.906 (steps/mm x)
$1 = 755.906 (steps/mm y)
$2 = 755.906 (steps/mm z)
$3 = 30 (microseconds step pulse)
$4 = 480.0 (mm/min default feed rate)
$5 = 480.0 (mm/min default seek rate)
$6 = 0.100 (mm/arc segment)
$7 = 0 (step port invert mask. binary = 0)
$8 = 4.800 (acceleration in mm/sec^2)
$9 = 50.0 (max instant cornering speed change in delta mm/min)
‘$x=value’ to set parameter or just ‘$’ to dump current settings
ok

Does any of the returned info seem like I might have GRBL on the 328 chip?

Most of my motor collection are fairly large NEMA 23 motors.

Does anyone have any tried and proven motors that they would be willing to share with me that I could purchase to use with the GRBL shield ?