I have a 1971 Marcos which has the B30 6 cylinder motor, to which I have fitted a B30E head (higher compression) and a mild cam (much the same as a "D"), but still running on Stromberg carbies (Yes, I know I need to change to SUs).

Well, over the Easter weekend I took the Marcos out to the local race track for my car club sprints - great fun, but ended up blowing the head gasket (5&6) turning it into a steam engine!!!. This may have in part been caused by it running hot - the plugs indicated it had been running too lean at full throttle, which was not apparent at normal road speeds.

Anyway, I can get a custom made copper or copper composite manifold made locally (I am in New Zealand), but was considering whether to upgrade the head bolts at the same time. I was thinking of ARP studs, but can only find kits avialable here and not of course for a B30 Volvo! I have seen mention of them on the forum so I assume they are available in the US.
At the same time I would like to add double valve springs as I also see this is recommended if running at higher revs.

Your thoughts and ideas on where to purchase the studs and valve springs would be much appreciated.

Thanks
Brian