I just put a pair in the cart and did everything but enter my personal info. It seems they are available. Also, the Twin Power shoes are Cycos, I researched it a while back in an old thread.

I will dissent on opening up and "having a look". The OEM shoes in your motor not only wear quickly but also are known break apart without notice because they're brittle. The below pictured OEM shoe was "inspected" and called good, just before it broke and caused problem$. At the least I would:

*Change the inner INA cam bearings for Koyo/Torrington B148s
*Change the shoes for Cycos
*(If you feel like it) Install a Baisley LMR-2 bypass spring/plunger
*Stud & nut the 2 doweled holes for mounting the cam plate
*Do NOT install the cam plate with the oil pump attached to it
*Install new GOOD lifters
*Change the rocker breathers for later stamped steel units
*Drill the rocker support plate oil return holes to 1/8"
*Mind the direction of the rocker box gasket so you don't block the vent hole
*ALIGN the oil pump before you button it up
*Mind the difference between the 1/4-20 bolts. If you mix up the longer ones you can dent the lifter bores

That said, I'm just a dude on the inter-net; I'm probably full of sh*t.

 

That's the first time I heard of mcspartparts. Have bookmarked the link. What made you go with them? Very interested!