How can I tell?

[Harpie]

Ok i decided to go with a Vortec 5.7 out of a 98 suburban for my engine swap instead of a 5.3 since I can make some nice cash off of my complete wrecked Tahoe. With that said how can I tell what engine towers I have the truck had a 402 swapped in it but was originally a 350 truck so was just curious before I go hunting parts and mounts since I'm about to have frame blasted and any other parts going back on.
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