I performed a large job for the company a while back and they told me that I would be taken care of on the overtime. It was a turnaround in the petrochem industry and I am a salaried position, however, this temporary position I assumed for the company was being reimbursed by our client, filled timesheets everyday and was worked over 200 hours of overtime in 32 days. I never got compensated for this and it was not my normal position with the company.

Am I entitled to the overtime for these hours, the employer new that this was outside my normal scope of work. And yes the job was successfully completed under budget, under schedule

What were the nature of your job duties? Exempt status is a function of job duties and sometimes the nature of the industry, and not the other factors that you listed. You might also look at the following.
http://www.dol.gov/esa/whd/regs/compliance/fairpay/main.htm