Yup, Copy a set of theirs. If you can do that you can also just fabricate your own factory type mounting perches no matter what K frame you're working with and just mate them to whatever style insolater you want to use.
$150 is not bad for the quality. I still prefer the DC k-member option, but I can build them for myself.
To answer your question, though, yes you can build your own mounts. Like said above the trans mount should be your reference point, crank should be parallel to the frame rails and the front about 5.5" above the k-member. Make sure you have enough clearance for the oil pump and whatever exhaust you plan on using.
thanks iv got a few more questions where can i take a good look at shumakers mounts to copy them? and can you guys send me some pics so i can see what im working with!! what im worried about is getting it off to one side or the other the slant 6 k frame is a weird one! what i was gonna do is.. the drivers side on the /6 kframe is off set to adjust to the "slant" of the /6 i was gonna cut it off and weld it back where it needs to be and then make the mounts! please send as many pics as possible so I can see what yall did and then i can descide what to do thanks!