50-50 - no way. Let's assume you also come up with 100-150k, just to make it fair, because as Stonehenge mentioned, it doesn't ever seem to work out as planned. Now, you have some money tied up with a guy who wants to have 3-5 crews rolling. That translates into the need for a lot of revenue. In order to start that, without having the business already, or growing a midsize business up a couple of notches, your combined 200-300,000 isn't really going to be enough.
I think to net 80,000 for you, you need to determine who is going to work. Are you going to be paid to be a managing partner, and he gets 50% of profits only? Will you collect a fair salary, then split the profit after you are paid? That is a big question. 3-5 crews should gross about 750,000 - 1 million dollars, I think. That generates about 10% net profit in a tight ship to yield about 75-100,000. Split in half is about 20-30k coming your way if you leave a little in the company for growth. If you take out some benefits, and perks (like maybe a company truck), that profit will be down, and your partner will start to scrutinize what you are taking versus what he is taking. With a salary of even 40,000 per year, plus the profit split, I believe you will tolerate lower profits for a couple of years, and split 0 for 1-2 years. This is because you will try to enter a competitive market and ultimately offer a lower price to turn dollars. Otherwise, you will be paying your staff out of your pocket. That leaves you with a lot less money in the short term than you have now. Next, you will experience growth pains, due to the lack of middle management. Your partner probably won't even want to know about it until he realizes that the 75grand profit expectation was split down to 30k after you pay a manager........