Header explanation? Please

I really appriciate the intelligent comments here as i knew we did have people on here that have brains. Good stuff Maynard. Let's see if i retained any info that was submitted. If i heard it right, one needs SOME back pressure. If that's correct then if your exhaust valve i a 1.80" on the 440, then it would be ok to have a tube of a minimum of 1.75" thus creating a back pressure or venturi. The ill efects of unequal length tubes can also be corrected by useing cross overs or an H pipe. Am i on the right track. Tell ya what we've got. We're doing a 64 Savoy 2 dr post car. We want to do it right. The motor is a 440 punched out 30 over. It has 2.18 intake valves and 1.80 exhaust valves. Compression is at 12.5. Harlan Sharp rollers on top. As of now it has an Edelbrock DQ air gap intake on it with two comp series 500's. It's a 68 dated 440 and was sold to me as a 6 pk motor. I took it to the shop and had em tear it down and start over. It had new, never ran standard trw's but felt they were a little sloppy so we put in a set of 30 over trw's in their place. We're gona stuff it in and see where we're at. Just with what you know, what header would you start with if you were going to run it down the 1/4 or the 1/8 th. I have the choice of a 3.91 rear or a 4.68 rear gear all attached to an Eaton TruTrac gear drive sure grip. Any ideas guys?
Small Block