Good Day.... I have a blank that i got from a friend who passed. Is there anyway to test a blank to guess its specs? Line weight and lure weight.

Look at the Common Cents Info on the left.

If it's a casting/spinning type blank, you can possibly nail down a good lure casting weight with the Common Cents System, or you can just take a guess and go try some different plugs or lures until you find the sweet spot.

Line weight is more arbitrary than anything else. It doesn't count for much.

.............

At one level line size is a bit irrelevant as you rely on your drag to manage the strain for you.
if you are looking to get an idea of the approx line rating of the rod you just tie some line to the tip & a set of scales and tug on it until you feel the rod is fully loaded , read the scales and multiply by 3.
The rub is that the scale reading will depend on the angle you load the rod at ....................mostly this is done at 45 Degrees.
At 90 degrees ( as in static testing) the numbers will be lower...............at 30 Deg the numbers will be higher.
different manufacturers have different ways of generating this info.................45 Deg is a reasonable angle to approximate the data I assume you are looking for.

This an SWL thing for the line , not the rod............. and approximates the sort of line size numbers you see in blank catalogues.
the thumbnail rule being, stressing the line at 1/3 the maximum pressure the rod can deliver gives a safety margin for wear & tear, knots, and knicks in the line in fishing use.

some of the high end rod manufacturers are now specifying the load ratings for their rods as max drag and specifying the angle, as well as indicating the line size range and lure weight range the rod was designed for.

Rodmaker magazine V10-4, Uiniversal Rod Ratings. With all the fly to spin to fly topics that come up, I'm surprised it's not mentioned more. In addition to CCS info it gives you measurements for the butt and tip of the blank.

Jose,
The very tsimple thing to do is to take the blank with you when you go to a well stocked fishing rod store.

Simply compare the bending, tip movement, blank speed of the blank you have compared to built up rods on the display racks.

In just a few minutes, you will have a very good understanding of your blanks characteristics.

Once you have a built up rod with similar bending, power, and tip action as the one you have - copy the rod information off the butt of the built up rod.

Take care
Roger