Would dual headers give me a horse power boost and what is that install like?
You might get a little out of it, but doing the 261 cam and the higher compression head as Tim mentions will go further. If you do with the duals, be prepared to do some grinding to make them fit. Otherwise, they mount up the same as the stock single exhaust manifold does.
If you can't find the later style head, your stock one can be milled to bump up the compression, but you;ll want to find a machinist that knows these engines to do it so that too much isn't taken off.
