Extra hp out of my 340.

I agree with Ir3333, leave it alone. The power you have is nice and the engine compartment is even nicer. However, we all want more and so do you. Problem is, neither of us know exactly what you’re dealing with as far as modified engine internals and parts that are already in it. You could possibly open up a huge problem and then make it worse by mismatching parts because we don’t know what you have.

If I had to modify an unknown engine, the first thing I would ever do is a compression/leakdown test. This will uncover any problems or shortcomings you currently may have. Then I would install an air fuel ratio meter and tune the fuel system as much as possible, simultaneously with ignition timing. You can gain 20 ft.lb easily from a better tune. You’ll have to tune ignition and fuel anyways after bolting on any aftermarket part.