I have a 76 sierra that im gonna rebody and and rebuild the engine and such. Anyways the engine is a 4 bolt 350 with iron heads and my question is how big big are these heads with referring to valve size, combustion chamber cc's and if they are worth sending out to an outfit like Lloyd Elliot's to be ported or should i scrap them for some aluminum heads. If anyone knows what the specs are or where i could find the specs for my heads it would be greatly appreciated. thanks.

 

Should be 1.94 intake, 1.50 exaust w/76cc chambers. You can look under the valve cover for the casting # and look it up on mortec.com to make sure. Factory heads don't flow too well, and they went to lightweight castings (crack prone) sometime in the mid 70s, not sure when. It would cost $$$ to get them to flow well, add the cost of a rebuild, and probably not worth it. Only makes sense to reuse them in a stock type rebuild.

 

thanks for the reply, i was expecting there to be something up with them like the light weight casting or sumthing, but i'll check them anyways to see which exact heads they are. i'll probly just get a a pair of aluminum heads used or new . but again thanks for the input, it was helpful!