big valve head
Hello Andy, how much cash are you willing to spend? If you want a PBS big valve head you will be hard pressed to find one, used. I bought a used one a couple of years ago for a car that I am planning to build. but I have not started that project yet. If you are willing to spend some money for a re-manufactured big valve head, I can direct you to two different companies Midwest Bayless does not have the type of head you are looking for. However I called Vic Auto sport and asked them if they do a version of the big valve head and their response was that they make a head with over sized intake valves. I think they said 39mm. that head would set you back about a grand or more. You may even be able to get them to put bigger valves then that in there. I think I inquired about that. I recommend that you call them in person. I also think there is a core charge for the head unless you send them your own head. Your other option is to call Costa Mesa R&D in California. This company is familiar with Fiat X1/9 performance work and can also build you a big valve head. Go to You Tube and look them up they have a video of the making of an X1/9 big valve head. I am not sure what they would charge for their head, so you will have to inquire.
I hope this helps.
Regards Budgster