What will my payment be like on a 80/20 interest loan @7%?

The number of years the loan is amortized is needed for the answer.

By 80/20 are you saying the loan is for 80% of the purchase amount?

If so, that part of it doesn't matter. With the percentage and number of years, you can get the interest per $1000 of the loan.

You can even get an exact amount at an online amortization calculator, like here.