I have been told it's 1.65:1 and that was what I have baised my numbers off of in the past. If you know lobe lift, and you find the valve lift simple math can tell you what it is. You will have to round your number though to account for the oil pressure in the lifters. As you will slightly compress the plunger in the lifter without the oil pressure.
I'll be doing a cam swap soon and can check it and give you my measurements if you would like. But it will be a few weeks before it gets done. The cam has been ordered and it looks like it will be a little while before it arrives.