I have an 830 holley dp with mech. secondaries on my 396 it runs fine until you rev it up then a fire starts in the secondaries. The carb is stock.
What is the probelm? Also there is no place to hook up the pcv or vaccum advance.

It sounds like the engine has a missfire in it somewhere. Carbs just don't start fires by themselves.

First Check your timing. Your initial or your total could be too far advanced. If your timing is on the money, then your problem is in the valvetrane. AS stated above, carbs do not spontaneously combust.

I have the timming at about 10 intial I don't have the vacuum advance hooked up because there are no vaccuum ports on the carb that I could find. I also have an exhaust leek between the #8 exhaust port and the header but this never cause a probelm with the 600 edelbrock.

Check again for vacuum ports. Unless they were plug off on purpose it should have one for the PVC, one for ported and one for manifold vacuum. PVC is in the rear of the base plate and pretty big. Ported is on the right side of the front metering block and manifold is at the front right side in the base plate. A lean condition can cause a carb fire. An HP carb might be different but a standard 4150 should be like this.

It is the 830 race carb no choke and I am pretty sure no vaccuum port I looked for them before I put the carb on.