I had Ed build me an oil pan with enough setback of both the front and
rear walls to allow 1"x2" .065  rectangular tubes to mount using the oil
pain bolts.  These tubes are very strong, light and avoid the heat and
weight issues of aluminum flanges. The pan is about 4" deep and holds 6
quarts.  A 13B pickup tube is a little over 3", reaches almost to the
bottom of this pan, and will fit on a Renesis engine with minimal
modifications.  Overall, this is a simple and inexpensive way to make a
'bed' type mount.

My rear (pusher) mounting tubes are relatively short, so they have
plenty of strength in all directions.  A longer engine-to-mount arm of
this same dimension would obviously need appropriate calculations to
assure it is strong enough.

Scott Gettings