Thanks- I am familiar with Stamm tractor having bought some seat cushions through them before. They have them on listed on the computer at a reasonable price and I have a e-mail in to them but he travels a lot so maybe they can help.
A place I know has some new-old stock 10A4010 heads which they say will work but increases Compression and some modification and costs way more than I wanted. May have to go that way yet.
Would that be a good or bad upgrade?