I have two set of heads:

1. Casting #39447041

2. Casting #3973487x


I like to get some more info on these heads, and which set would you use for a mid 80's chevy short bed truck?

Is it worth putting in 2.02/1.60 valves in and about how much difference will it make power wise?  

The 041 heads have 64cc chambers and the 487x heads have 76cc chambers and both heads could of came with 1.94/1.50 or 2.02/1.60 valves depending on application. I would use the 041 heads instead.