Let's Build a 416 with Cast Iron Heads and Manifolds

500hp? wasn't the goal 12's and looking stock?

Never said or was making a point that LS and 340 manifolds are same or 500 hp with manifolds is a piece of cake, talk about nit picking. I just googled manifold vs header to give the OP some idea what he might expect and was surprised there was only a 10 hp difference.

But I doubt there's a major difference between manifolds, 318 vs 340 are only 5hp difference on a 300 hp engine, I highly doubt LS manifolds make more than 5hp over 340 manifolds even if 10-15hp that's still a 418hp engine. Even if they kill 50 hp on a 550 hp 435 W2 engine = 500 hp.