This weekend Dad and I were debating a motor for his project truck. He wants 500HP (at the crank) all motor, no power adders. He thinks we can upgrade the existing engine, which is an L31, a 265HP 350 V8. It’s got Vortec iron heads and not much else going for it. Also uses a funky fuel spider with non-upgradable 19# injectors, so the entire top end has to be redone.

I’m pushing for an LS swap. I’ve seen some amazing stuff with the LY6 - it’s the 6.0L V8 out of the newer Silverados, Suburbans, etc. Its an iron block with LS3 aluminum heads and in-block VVT. It also makes 385HP bone stock and they are available for around $2000-2500 with ecu, harness, and accessories. Mast Motorsport makes a VVT-HO Cam kit that, with an LS3 intake swap and headers, puts down 420-430RWHP, which back converts to about 500HP at the crank.

So what say you? Keep the old iron or go high-tech?