I'm doing some head work to my H89 A15 head and I've read here that putting the L16 ex valves is a good upgrade. Now which size should I go the 33mm or 35mm. Rocker assembly will be standard. I'll have double valve springs, twin side draught webers. Cam. Ported and match ported head.

Also with putting in the L16 valves which guides/stems do I use. The A15 or L16's?

Thanks