I'm working 40 hours a week on a set 4 day 10 hour shift schedule with one hour unpaid lunch. When would i be eligible for full-time benefits?

This is maybe complicated. It is perfectly legal for employers to never offer any benefits to any employee. There is nothing in federal law and the law of most states that requires employers to offer benefits. However, if the employer chooses to offer benefits, then the depending on the type of benefit, the government may compel the employer to follow their benefit plan rules.

This distinction is important. For example, no employer ever has to offer a 401(k) plan. But if they do, very bad things happen to any employer who fails to follow the exact wording of the company's 401(k). And the wording of 401(k) plans can legally be very different from company to company.

Now not all benefits are legally the same. 401(k) plans are subject to two very strongly enforced laws (IRC and ERISA). Violating a 401(k) plan is a big deal. Violating a vacation plan may be a modestly big deal, or nothing at all, depending on a bunch of things. A particularly foolish employer could fund their vacation plan and bring it under the federal ERISA law. But 99%+ of all vacation plans are not subject to ERISA, are subject to state law only, and many states do not care much, and more states basically just say "follow the plan as worded".

So, the short answer is that you need to read each and every one of your company's benefit plans. You cannot assume that the same rules apply to each benefit - they do not. You cannot assume that what is true for some other company is true for all companies - this is also not the case. But to the extent that your employer has formal benefit there is at least a chance the government will enforce the rules of the plans. Those plans subject to the ERISA law such as 401(k) and most medical plans are enforced by the federal government. Benefits like vacation are generally subject to state law only, which means every state can and probably does have different rules. But it still worth reading the exact language of the plan and maybe showing it to a local attorney.

And the even shorter answer is, what does your HR Representative say?