Big Block perches 1972 GMC 2500 LS swap

[1972GMC2500]

I'm trying to get everything ready to transplant a 5.3l LS into my 1972 GMC 2500. It has a 402 in it now. Can I use the big block engine perches, or will I have to buy some SBC perches. From the pictures I have seen, it looks like the BBC perches are just a few inches higher. Several of the aftermarket perches I see say that they can be used for SBC or BBC. I understand I will have to buy some LS mount plates to mate the motor to the factory motor mounts.
Thanks.
Gregg