Ok, the old guy is chiming in again. Sorry, but I was a fan of the Big 33 back when the game pitted PA vs. TX all-stars. I was living in San Antonio by then (my brother, however, was still considered a resident of PA in his junior year at PSU), and PA had challenged Texas in the game.
In 1964, Texas still held its annual North-South High School Coaches All-Star game around the same time as the Big 33; therefore, the Lone Star State sent its "back-up" 33 up to PA for the game. The high school coaches’ game was a highlighted event across the state. I recall reading a Sports Illustrated article about the game
Well, when the game ended in a PA victory (something like 13-6 or close to that), the folks down here were irate. The feeling was "Those Yankees beat our second team." The state administrators who were in charge of the organizing the Texas half of the event promptly went to work to ensure such a drastic upset would not happen again. They convinced the high school coaches to move their annual game to a different, non-conflicting date, so that more of the top players in the state went to Hershey. Then they hired ex-Longhorn and NFL QB Bobby Layne to coach the Texas squad.
In 1965, PA had Mike Reid (who I think even kicked a FG for PA) and Ted Kwalick, but lost in a relatively close game 26 (27?)-10. I remember Kwalick having a great game, but TX had the legendary "Super Bill" Bradley (UT) as its QB and SMU star Jerry Levias at WR.
But a 2-touchdown win wasn't enough for the Texans. This game now took on state pride, and Layne convinced the high school coaches to send their very best to PA, unlike 1965 when some coaches kept their players for the in-state all-star game. So in 1966, Texas had SMU star Chuck Hixon and famed Longhorn James Street as its QBs; PA countered with 22-0 PSU QB Chuck Burkhart. But the Texas defense stuffed PA that night for a 35-2 rout that made the Lone Star folks happy. The game was shown on closed-circuit TV in the famed Majestic Theater downtown, and the place was sold out. I was among the viewers, decked out in PSU attire. It was a miserable night for me.
The 1967 game was the last one versus Texas, as it likely became clear to the Hershey people that the talent levels were not quite equal. Texas won the final game 45-14 behind QB Tim Montgomery who went on to star at Arkansas. Steve Worster of Longhorn fame as a Wishbone FB was another star for the Texas team. I can't recall whether any Penn State player had a good game.
I lost touch with the Big 33 after that, since it no longer made local news. Texas developed a rivalry with Oklahoma in a game called the Oil Bowl, but the state all-star game returned to its status as the prime event for high school players.
I apologize for errors in precise facts like final scores, but I think most other info is accurate.