Well, here are the measurements that i got from a guy on the srv540 website to put the xtra10 in my srv. The measurements came from the donor sled, so they should apply to any sled you are going to put an xtra10 in, tho I would mark them and be sure they make sense first.
I'm not sure who gave me these measurements off of the srv540 website, but he deserves the credit, not me.
That being said, here ya go:
97 XTRA-10.
It's in a 90 SRV.
From the back of the drive axle, the rear hole was 34.5 inches.
Front hole is 23 inches from the rear, center to center.
Both of my holes are 5.5 inches from the top of the tunnel. (might wanna go 6" for more adjustment)
I measured off the back of the drive axle, as it was easier.
If you do measure from the back of the drive axle, make sure you are on one of the flats, as the axle is hex shaft.