Originally Posted by JohnZ
I'm not positive, but I believe the trap-door pan (3769761) was only used on the solid-lifter engines; others may have better information.
I looked the other day in a '61 P&A book. It lists a single pan for the '60-'61 solid lifter engine. Doesn't say it's trap door but I know the OEM solid lifter engines used a trap door pan.
There's a different pan released for the other Corvette engines of that era. The book lists the pan as "all" which would mean Pass car, Corvette, light truck. '58-'61, four quart.
Be advised, this is service replacement information, not necessarily the same as OEM.