65 K20 Wheel Help

[654x4]

I need a little bit of help...

I bought a set of transwheel #1619 wheels for my 65 K20. My goal was to replace the split rims and original tires with radials.

(They look like these, minus the caps: http://www.wheelsandcaps.com/p-23631...6x65-1619.aspx)

When I was attempting to install them today I discovered the fronts won't completely bottom out on the hub/drum. They are extremely close to fitting but apparently the originals have an ever so slightly larger hub hole.

I took them to a local machine shop to have them opened up a bit. What I'm looking for is the dimension of the correct size hole to make sure he can get them right the first time. The original wheels are 17" split rims with 7.50-17 tire.

Can anyone help me out with a dimension to use or other info? I attached a pic of the new setup.

Thanks a million.