new motor

[mcguire22]

well, I got my motor in(283 out of a 65 impala). First, let me tell you what it has. Lunati cam, weiland intake, edelbrock carb, and headers. The thing idles great but as soon as I give it gas it backfires. Then it started backfiring when at idle. So i got it home from the shop and its overheating( brand new waterpump). Any pointers with the backfire? It still has the 6 cylinder radiator but it started overheating pretty quick after I started it up and timed it. By the way, I set the timing a 4 degrees. Does that sound right with the mods. Thanks for your imput, I know it will be great