a monoblade would simply be rated in CFM's...

So lets sum it up-
U cant use an LT4 intake with LT1 heads "It features raised intake runners for inporved flow and proper port alignment for LT4 cylinder heads. "
52mm is max bore on a 48mm housing
Bigger isnt always better ie velocity

Consider going to 52mm when u have 400+ flywheel hp.. or if u have 360ish and reving to 7000rpms instead of 5700rpms..