It's been a few years since I instructed High School, but I remember it fondly.

OP, your projects are outstanding and will have a lasting impression on your students for decades to come. Incredible work on the Ford.

As for the heads and carb? Focus on the value of the lesson. What lesson is of greatest value, greatest learning potential?

Have the students port the factory heads. Start with another set, or sets. Maybe Chevy heads. Teach them patience, form over size, velocity over volume, equalization, and bit and tool use, preservation, and care.
Teach them to be conservative in their approach.
Teach them the value in reading and researching known good techniques, homework assignment.
Teach them to disassemble, measure, remeasure, assembly, etc.
Teach them the value in honest, hard, quality work with what they have instead of how to spend money for someone else's mediocre effort.
When you have a few that are committed to good head work and show that they have developed the skills necessary for a minor port job then set them loose on the factory heads.

Bracket racing? Teach them about consistency and reliability instead of how to purchase speed.

If they learn how to make what they have work for them then they will be more likely to succeed with what they have.

And, show them how to budget and prioritize through example.

Use the heads you have and use the carb you have. Use the converter you have and use the gears you have. Teach it like it's 1975, and there's little to no aftermarket options and they'll have the foundation to make anything work for them. Purchase nothing, borrow nothing, steal nothing. Your goal is not to be the fastest, or even win the race, but to build skills, expose talent, and develop a love for the craft. Build the character by building the car. When they are grown the skills will pay for the pretty parts, not the other way around.
Best of luck.