It does not sound like the OP is suggesting or hoping to match header power with manifolds.

My junk is pretty simple. 120 mph at 4150 lb in a car with basically a stock factory suspension. Seems like okay power to me. If it were any faster I'd need a roll bar, and that is not going to happen. It will drive through the neighbor at 1100 rpm in third gear with no problem.

I did choose to purchase a roller cam, but here is what I did not have to purchase: headers, starter, 3" exhaust, converter, gear, tires.

Certainly not the fastest car around, but I wish I had a dollar for every header car I've spanked.

Personally, I would not put headers on a from scratch build unless I was also planning to install a roll bar.

As mentioned, it is a matter of what the OPs goals are.