Welcome, Bill.
I can't help with new studs, but I have several old Vanguard engines and might be able to replace bent studs. (However, these engines were in a back yard for years.)
An obvious solution would be to get new studs through the Triumph Razoredge Owners Club, but their insurance won't allow them to sell to parts to their American and Canadian members.
Most owners of Vanguard-powered Plus Fours have replaced their Vanguard engines with TR3 or TR4 engines. Alternatively, one owner kept his Vanguard block but replaced the cylinder head with a TR3 head. (This is my current plan for my own 1953 +4.) Since this approach should be relatively straightforward for you, I'm guessing that you want originality more than performance?
Pat
