If you are buying a set of heads I would wait and do it all at once. Then you can be sure it will all work well together. If you buy a intake to complement your gt40's chances are that if you get a good set of heads that flow enough for a 347 your intake will be a restriction again. Not to mention you will be diong twice the work if you put a intake on then do heads later. I would get a set of victor jr's, ported trick flows, or canfield heads with a systemax II, trick flow R, or victor 5.0 intake. Throw in a wicked custom cam and you will be set. You will be doing 11's at the track n.a. I have a setup like this and I have massive top end with good grunt down low.
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NA 347 W/ stage 2 Canfield heads, out of the box Victor 5.0 intake, solid roller cam, Aeromotive fuel system.
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