4V heads have a "4" cast in the corner, 2V's a "2". 4V's intake ports are larger. If you want a good visual do a side by side comparison of intake manifold gaskets. The ports for the 4V are 1.88 x 2.65, the 2V are 1.50 x 2.12. As for the pro's and con's I'll let the experts cover that. Don't forget the quench and non-quench question in addition to the 2V vs 4v!
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