440 timing pinging and popping thru exaust
There are a lot of variables when it comes to setting timing that make it difficult to give exact numbers. Camshaft design, compression, the quality of the gas, weight of the car, etc... If we assume that your harmonic balancer is 7&1/4" in diameter (as all of the 440 ones were that I've seen) then you can make some marks on your balancer to coincide with the degrees you want to hit with the timing light.
If you use the calculator on your computer you can figure out how far from the TDC mark to scribe your new lines. Taking 7.25" times pi you will come up with a circumference of about 22.765". Dividing that number by 360 will tell you how far apart the degrees are on that balancer. It comes out to .063236111111. I know it sounds like a squirrelly number to have to deal with but just take that .063236111111 and multiply it by the number of degrees away from TDC you'd like to see your new mark.
As an example, if you wanted to mark your balancer for 34" advance it would come out to around 2&1/8". You could use masking tape and a pen rather than put a permanent scribe mark down. One nice thing about the masking tape method is that you can do your measurement on a bench. Just make a TDC line and measure away from it to where you want to draw your next line(s). You just line the TDC line on your tape with the TDC mark on your balancer. You may find that the tape method is easier to see with your timing light too.
Most builds that I've seen similar to yours don't go past 36' for total advance and it's usually all in somewhere between 2500 and 2800 RPM. It will probably take a little playing around to figure out what's best for the exact combination you have. I wouldn't suspect bent pushrods or any other major motor snafus yet. If it ran great before the distributor swap you're probably going to find the issue with your distributor. One of the nice things about a digital timing light is you have an RPM readout right in front of you as you're reading the timing. You'll be able to tell if the advance is coming in right about where you want it.