I'd be curious what a stock 69-70 340 avs intake would flow and compare the two. All the reading I've done over the years says the stock manifold was pretty good right out of the box, and that the ld340 was really just a copy in aluminum - 5 HP at best over the stock intake. Same goes for the current aluminum dual plane MP offers for the small block - it too looks like an aluminum copy of the factory cast iron avs intake.