steam holes

[spookie]

With a chevy 400 block,and aftermarket heads. What happens if you don't drill steam holes in new heads?

[dreracecar]

Is this a daily driver or a race car???   no water - no steam

[spookie]

Engine going in FED. Will have cooling system,but not sure what type fuel.Owner just wanders if he should take back apart.

[Roger]

If you're only running it a quarter mile per at a time, you can probably get by without holes. The steam holes are only needed when the engine is running hot for a long period of time because of the siamesed cylinder that don't allow for complete water circulation in a stock block. The two center exhaust ports are close together and also tend to concentrate the heat at the deck which the holes help with circulation and cooling.

[dreracecar]

If the fuel choice is Alcohol----

 Iron block and iron heads--- then no cooling is needed, leave the core plugs out  to let it vent
 Iron or aluminum block  with aluminum heads then water only in the heads to keep center exhaust area from burning out

 if the plans are o-rings then the alu head gets the o-ring and the block gets the reciever groove, again to keep the exhaust area from burning out

 You can use MLS gaskets for Iron blocks and heads,  I havent had good results with the MLS gaskets with aluminum and best to go with copper if the engine is blown

[jeff/21]

Ran 406"with both cast and aluminum heads with no steam holes but the block was filled up to 1" from the deck with water in top end mls gaskets