I am a bit concerned about my valve spring tension on my m20. The small valve lifter lever on the barrel is easy to depress with your thumb is this normal.

It is rather easy to lift the valve like that.
Says nothing about your valve spring condition.
If ever you have the cylinder removed, you can check the valve spring length.

yes i have a new head with all the fins to fit but the head on it has hex head bolts (allen keys) why i dont know. They are very tight with a ten inch pipe.

The head bolts should be torqued to 28-30ft/lbs, tightening down progressively and following the sequence in the workshop manual..Ian

email (option): ian@wright52.plus.com