need help identifing my engine..

[heavy71chevy]

I have a 327 that im rebuilding for my truck with the works but how do I detrmine if my motor uses standard 5.7 rods or not? My motor came from a 1964 impala and some external mods but nothing internal,as in it was still stock internals but..The summit tech that I talked to recently told me they should be standard 5.7 rods but I want to make sure that this is correct info before I drop the money for the rods and pistons..Is there any sure fire way to ID a small journal motor vs. a large journal as I dont have a 350 crank to compare to..Im using keith black silvolite pistons and want an H beam rod and this whole thing has got me very confused