I have a 16M engine and I am confused by what Alfin barrel will fit , what is the flanged type? Were that that many different Alfin barrels? Does anybody know how many were made?

Which barrel you need depends on the year of your engine. To keep it simple, if you have an alloy cylinder head you will need an alfin barrel with a flange/spigot at the top. If you have a cast iron or bronze head you will need the barrel without the top flange.

Happy hunting, Alfin barrels do come up regularly on ebay, but are not cheep. An alternative is to fit an alloy top end from a 500...

the alfin barrel, as opposed to an alloy barrel, was an after market item that replaced the iron barrel. They were flanged mounted to the crankcases, using the four studs. the alloy barrelled

comp motor have long studs through to the head to fix them. The stud configuration is different but can be made to fit but not easily.

Iron heads were pre 1948 I think. I have been around A.M.Cs literally all my 58 years but have never seen a bronze head on one.

Thanks for your replies, the engine is a 1948 AJS 350 16M  and I was wondering about using it for trials and wanted to get an ALFIN barrel to fit

Was there a flange at the top as well as the bottom. Is it a straight replacement? 

Being a 48 yours is the change over year. Is it alloy or iron headed? To be honest I wouldn't know if you get one to fit an iron head.

It takes more than an alloy barrel to make a trials bike, get the gearing and handling sorted first, then start to make weight savings.

Thank you for your replies, I have an alloy head which I am told should be an iron head, as for the handling and gearing. 

Gearbox already sorted as is the front end. Just need some help with the set up of the rigid back end which I already have the Reynolds tubing waiting. Just concentrating on cutting weight where I can. I think the  alfin barrel and the original iron barrel there is only a 2lb weight difference which I recently found out. I think I have found a place where I can get a big chunk of alloy billet so may get one turned up.