Your first though when you see him is that “High School Musical” alum Zac Efron is the beneficiary of the latest tech used to make “The Hulk” come to life.

He is a walking muscle, bulked-up so much his head seems an immovable object riveted onto his neck. The bulging muscles of his legs and simple bulk of his body affects his forward motion, forcing him to sidle into scenes rather than simply walk in.

It’s a stunning transformation, and whatever he went through to achieve it, that speaks to his commitment to “The Iron Claw,” a “true story” of wrestling, toxic masculinity and the dreams of the father pursued without much choice by four sons of a onetime pro who never got that coveted world heavyweight title belt.

The latest drama from writer-director Sean Durkin (“Martha Marcy May Marlene,” “The Nest”) is a tale of God, guns and steroids and the performative masculinity of a sport and “scene” seemingly tailor-made for Texas.

It’s about the Von Erich clan, four young men trained, tested, taunted and bullied into the ring by their father in pursuit of his dream, to settle his “grudge” against the wrestling establishment that never gave him his shot.

“Fight Club” and TV’s “Mindhunter” veteran Holt McCallany has his chewiest big screen role in years as that patriarch, Fritz Von Erich, who “ranks” his sons in terms of who is his “favorite” determined by who has the best shot at that elusive “belt.”

He’s not physically abusive, just uncompromising and demanding, running his family as part of the Texas wrestling business he bought out in his later years. His boys will be “the toughest, the strongest and absolute best.” And they’ll get their shot.

If not Kevin (Efron), the best looking and bulkiest of the lot, then it’ll fall to towering, charismatic David (Brit actor Harris Dickson of “Where the Crawdads Sing”). If not David, then Olympic prospect Kerry (Jeremy Allen White of “The Bear”) will change sports and he’ll be The Chosen One.

Skinny, musically-minded Mike (Stanley Simon)? Well, let’s hope it doesn’t come to that, right?

Kevin is our single-minded narrator, the one who talks about “the family curse.” Not only was Dad unable to reach the pinnacle of success, but he lost his first-born son before the lad reached his tweens. His other boys become his project, working out constantly on their Texas ranch, roughhousing and bonding when they aren’t body-building and getting shots in the rump to aid that bulking up.

Kevin’s handsome and unworldly, a bit shy. Naturally he’s bowled-over by the brassy fangirl (Lily James) who asks him “What do you want in life, Kevin Von Erich?” His dopey answer, “to be with my brothers,” gets a cards-on-the-table reply from her, and our great big wrestler turns into a lovesick puppy.

As Kevin isn’t a natural at the rehearsed and “performed” trash-talk that promotes TV wrasslin’, he’s facing an uphill battle. David, on the other hand, has that shtick down, always using the family’s trademark wrestling hold, “The Iron Claw” as his punchline.

Kevin’s sensitive enough to see the toll all this competing and paternal pressure is taking on himself and his siblings. Mom (Maura Tierney)?

“You work that out with your brothers,” is her dodge. “That’s what they’re here for.”

The film tracks the Von Erich (original surname Adkisson) clan through the ’70s, taking its best shots in the ’80s and coping with “the family curse” that is their father’s excuse for when things don’t work out, often with tragic consequences.

Of the performances, Efron’s startling transformation impresses, letting you see the limits it imposes — physical, emotional and intellectual — on poor Kevin, who like most of his siblings, has little else that he’s fit to do in life. At least he gets a dance number — a boot-scuffling line dance with his brothers.

The film on the wandering wrestling family that settled in Texas dabbles in the rigid gender parameters imposed in their world and the violence even in a “rehearsed” and “staged” sport. Those tables they and their great “national” rival, Ric Flair (Aaron Dean Eisenberg, a hoot here) crash through, those folding chairs that make handy weapons, those concrete floors they’re doomed to land on, hurt and cripple.

Durkin’s longish and thorough (“ish, as he left out one brother) account of this family, its sport and its “curse,” can feel cursory, as if he hasn’t made up his minds about all this when filming finished. McCallany has too few scenes and Fritz feels watered down, perhaps owing to family sensibilities, as a brute who scarred his brood for life.

The film plays as a “Great Santini” in which no one stands up to the bullying, controlling patriarch. That makes it more an observation than anything Durkin is drawing a conclusion about.

The performances are good, the wrestling thrillingly-shot and cut together. But with a meandering message and an ending that is almost a parody of the “paradise” these boys reach for, it’s forgiveable to consider “The Iron Claw” — scripted and acted to the limits of what the script serves up — as little better than a draw.

Rating: R, violence, steroid abuse, sexual situations and profanity

Cast: Zac Efron, Lily James, Jeremy Allen White, Stanley Simon, Harris Dickinson, Maura Tierney and Holt McCallany

Credits: Scripted and directed by Sean Durkin. An A24 release.

Running time: 2:10