Usually windage trays bolt to the main bearing caps using special bolts ,
trays are usually separate from the oil pan. I doubt if a tray is necessary
on a 305 I/O. Anyway, take the old main bearing cap bolts off the old block
and install on the new motor. Be sure to torque them properly. If your new
motor can not accommodate the tray by just swapping bolts just forget the
tray,don't switch the caps. Be careful not to change the placement of the
main bearing caps on the new engine.
Also, your old oil pan may have had some special fittings for oil draining?
Other things to check on the new engine is raw water cooled, use your old
water circ pump, may surethe new engine has brass freeze plugs and you have
a head gaskets that are suitable.A marine (or automotive RV)camshaft would
be nice to have too.
--
Ron White
Boat building web address is
www.concentric.net/~knotreel