Ok. I recetly purchased a used lt1 from a 95 impala ss for a repower in a 83 Z28. it has cast iron heads, but i don't have the numbers handy. Does anybody have expiriance with using cast iron factory heads on an lt1? I've heard they flow more than the aluminum heads, and almost as much as an lt4, but who knows if thats correct. i have little expiriance with the lt1, and any info would greatly help.

 

As stock,they flow a little better than a stock aluminum head, but I don't think they compare to an LT4. The drawback is the weight and lack of heat dissipation as well as ease of porting. Even as compared stock to stock, you can usually get a little more power out of the aluminum heads as you are able to run more timing without heat issues. Those are some reasons why people opt for the aluminum heads.

 

For a document that is probably close to 12 years old (maybe more), this is still an interesting reference with regard to flow tests run on the stock heads:

http://www.malcams.com/legacy/misc/headflow.htm

 

Keep the iron heads till you are ready to go to ported aluminums.

Yes there are "reasons" everyone wants the aluminums but that does not mean all those "reasons" are good ones.

 

Am i right to assume that gm made vortec heads directly off these heads? if thats the case, could little porting and the right cam net me a head worth about 400-415 hp?

 

Yup, 400 isn't tooo hard with a cam and some good heads.

 

fricken awesome. thanks for the help. I'll have to do some more research for vortec head porting, because i do know they lack on the exhaust side.

 

The Vortecs are a standard cooling flow version of the LT1 iron heads. Not exactly the same but solidly similar.

Keep the porting pretty superficial which you should as a novice anyway and you should be OK with the iron heads. Guys who have ported them heavily have later had them crack in areas they made them thin. The head is VERY reliable if not heavily modified. Things like head gasket failures are far less common with the iron heads.