I have the actual Elco builder's plans ,however, the original frame drawings are missing/unavailable. These are very large sheets. The plans from John Lambert are the best bet.
It can be confusing because the term PT Boat refers to two seperate designs which were mass produced in the USA, namely, the 78' Higgins and the 80' Elco. These two 'PT' boats were quite different designs and the Elco was built in larger numbers.
Often U.S. forces personnel talk of the Higgins boat and actually mean/refer to the small plywood landing craft which was used in large numbers to ferry troops onto hostile beaches both on D Day and during the Pacific campaigns designed and also built by Higgins.