My literature shows that the 702 and 351 have identical wrist pins at 1.240".
Bore is a nominal 4.562 (4-9/16) with standard oversizes at 0.020 and 0.040.
Rods are the same as a 401 V6, and I believe a 351 also.
Looks like Kanter sells parts, I have requested their catalog.
I think hydraulic Lifters are the same as a 235 / 261
I have seen Egge pistons before, while suitable, I don't think they are as good as the real thing.
I too think Ross could make them, but at what price?
I am still thinking that there will be some genuine GMC pistons out there somewhere, or some NOS replacements? Or even new ones from a regular engine parts store.
Grigg