Gaoyue,
Thanks but i saw the SP resin kit have some erior on the hull too, we made the handmaster for some versions of T-64s I put the pictures up so you could look them over, to make sure details are not being missed. With the production of the T-64 spanning 25 years, I am sure there are a few detail differences in the lower hull, and no I do not know what they might be.
With the chronology as follows:
1963: production of T-64 with 115mm main gun
~1967: after 600th T-64 production, T-64A production begins, with 125mm main gun.
1976: Production of T-64B
Between 1977 and 1981 almost all T-64 (initial) were rebuilt to T-64R which made them similar to the T-64A except they still retained the 115mm main gun.
I can see with all that, maybe some small changes to the lower hull may have taken place.
Also, SP Designs parts are made to improve SKIF kits. I would like to help see that the Trumpeter kit comes out much better than anything on the market, including SP Designs and Miniarm.