I have a set of 837 heads cast iron heads. going into a 00 chevy truck. Dropped a valve. Valve hit the guide on exhaust. Intake guide is cracked. Not really sure i want to mess with them. Thinking about just getting a different set.

My real question is. Can i get an aluminium heads? or do they have to be cast iron? Does casting number really matter?

 

You can put on aluminum heads, casting number does matter. SOme make better power than others.

Good- 5.3L heads, crappy flow but more compression will boost power some ($100-150)
Good - #2 - #317 heads, good flow but large chambers, stock aluminum version of 6.0L heads (~$200)
Better - #243 heads, good flow and smaller chambers. Power from flow and compression ($400)
Best - aftermarket / CNC OEM heads ($1000-3000) will make more power than all the others

 

Thanks. Good info!