tuning a magnum

I was told by a wise fuel guy that one out of every 4 needle and seats is worth a dam. I went through 12 to find 3 good ones. They will hold back 11 psi!

Stick to the basics first.
Do a compression test. Spray the intake to check for vacuum leaks etc, etc.

Check your distributor for proper indexing, most Mopar Dizzy's are off. Period! Drill a 1/2 " hole in an old cap and watch what your rotor is doing. You might be amazed.

Is the motor properly grounded, each head, the block etc?

Send your carb out to a reputable carb expert along with your car's specs. Have them go through it.

That's about the only thing that will cost you a little money and time while they have it. I've used Ben at Promax and recommend his work.

How is your fuel system plumbed? is your pump below the level of fuel when the car is sitting? Did you put the pressure regulator in front of the carb and leave it soft mounted?

Where is your fuel pick-up and is it 1/2"?