Yuta

Just took apart a project EF with B20 swap in junk yard today... Looks like there is no mount in the front (transmission to front sub frame). There are only three mounts, front, left and rear. So that is all you need for B20 swap? No front mount needed?

acmoc

depends. If they're aftermarket poly mounts then you can get away with just three.
Oem mounts, you should have all four.