Hey guys i have a LT1 and building it up. It has the iron heads bc its from a ss impala. Now should i keep my money or will it give me any hp? Then how big of a weight differences is their?
thanks
kevin

 

The stock lt1 iron heads flow more- but not by much over stock lt1 aluminum. aluminum heads are about 50lbs less then iron heads. stock for stock no real advantage to switching but with aluminum you'll knock weight off and there much easier and faster to port then iron... look on ebay for a set there fairy cheap then sell the iron ones to re-cope some funds if thats your plan

 

Iron LT1 heads flow about equal to the LT4 aluminum heads. Not spectacular by modern aftermarket standards, but still fairly well. I would leave them there, unless you are looking at TFS or AFR heads. The only advantage to the factory aluminum heads is the compression gain (roughly 1pt.... 9.5 to 10.4) but that much won't make a significant power difference when you factor in the lost airflow when going to the aluminum heads.

...I'd suggest waiting to do the heads untill TFS releases their new LT1 casting. 21* valve angle, 185cc ports, 54cc chambers, flow numbers around 280cfm/210cfm @ .600 valve lift. Fantastic looking heads. Supposed to be released sometime this month or next. They can use a stock LT1 intake as well, no need to change to the LT4 intake.