The pair are set to clash in a high-stakes shootout across the eras on August 21 in Las Vegas, Nevada.
And Garcia, who hasn't fought since his victory over Jessie Vargas at Ford Center in February 2020, has given a slight edge to Spence Jr but admits there isn't much in it.
Speaking on the ESNews YouTube channel with Elie Seckbach, Garcia gave his prediction: "The youth, the size, and skills, I feel like that's going to help him [Spence]. So I'd say 60-40 also.
"It’s not an easy fight either. It's not going to be an easy fight for Spence.
"Pacquiao is going to have a lot in his arsenal. He’s got a lot of experience, quick footwork, fast hands, power."
Having taken some of his best shots on the chin, Garcia believes that Spence doesn't have the strength to severely injure Pacquiao, but insists that he will still be able to finish the job.
"It’s not an easy fight but I just feel that Spence is a fighter that can make the adjustments well and figure out what works and what doesn't," he added. "I think he is going to win but in a good fight.
"I don’t think he stops Manny, a lot of people think he's going to stop Manny - I really doubt that.
"I don't think he stops Manny. It’ll go the distance."
Garcia also recalled the first time he came face-to-face with Pacquiao when they met in a sparring session in the early stages of his career which he says caught him unawares.
He continued: "When I sparred Manny, it was a long time ago - different time, different weight class, different age, loads of different things. But his style of fighting has pretty much always been the same.
"I remember the very first punch... we went into the centre of the ring, he threw a straight left right away. I was like, 'oh f---'.
"That was the only time he caught my attention like that."News Now - Sport News