I have a set of cast iron heads done by dutweiller, they have bigger valves bigger springs, and fulley done ported and polished by the man himself have 1000 miles on after being done they were not flowed
they were done 7 years ago and yes i have paper work somewere I can call him to get it. i talk to him a couple times a month. he does great. would not be selling if not wainting to bild a ta block