js2fst

iTrader: (12)

I have a iron block 408 24 tooth looking to installing it in a ls3 5th gen. What is needed

FastKat

iTrader: (10)

Some sort of converter box to go from 24x to 58x. I know there are boxes to go 58 to 24, nut not 100% sure about going 24 to 58.

Everything else from your existing engine should switch over, including the front cover, intake manifold + fuel system, sensors, wiring, etc.

motion427

iTrader: (1)

I agree,seen 58x engine to a 24X ECM,but not 24X engine to 58X ECM.
You might need to replace the 24X wheel to a 58X and add a LS2 timing cover and the 4X cam gear to make it work.

redrocketSS

iTrader: (1)

Any reason for going with the iron block? Its much heavier and the 5th Gen is already a heavy car.