Where did I go wrong? Other than being a cheap ***

1980 360 with a reringed bottom end. Stock heads with no work done to them. Stock dual plane intake. Comp 275deh camshaft. Converter only stalls to 2000 before it starts pushing through the brakes. 600 cfm Holley vac secondary. Stock mopar ignition. And 4.10 gears with 29 x 10.5W slicks. Ran a 15.18 today in the heat. First time at a 1/4 mile track. Dropped from a 9.3 1/8 mile to 9.6 in differences in weather and altitude. Budget was little to none when I was building it. Now I'm not impressed and I wanna go faster but budget is still little by little. can't go out and order a set of heads or nothing like that. Maybe $300 bucks a paycheck to blow on her. So the questions is what to buy and in what order. Not caged or anything but I wanna get to the index just before I need to cage her