How much H.P. would a set of headers give me?

Long tube headers are worth a noticeable amount of horsepower, and a LOT of low end (if the carb is right). Even thru stock exhaust. More than the difference between pulling the torker or street dominator manifold off and going to a dual plane. In my book, they're a 'must have' for performance. And some PITA (depending on brand).

If you have a low-deck 361-400, you can use low-po "logs" like were on a C-body.

They can get a little close to the bottom of the steering column; I had to grind about 1/4" off the flange on my Valiant.

I'm negotiating to get the old girl back... and I won't be fooling around with any iron logs this time. But that's just my personal preference.

-bill