It depends on what You mean by "be careful".
Anything much past .460" will require machining the guides down for seal/retainer clearance, which the shop can do easily, & You should go to a modern PC type seal when thats done. If it's a 198 or 225, & low enough pistons for boost, the valves won't even be in the same zip code as the pistons so no interference to worry about there. Particularly if You're staying with wide LSA's. Guide ht. & proper valve springs are Your big musts there. Remember to add some extra seat load above the cam requirements for the boost, the more psi, the more You need to add when selecting a spring.
