12mm Decompresser Valves

[Baff]

'Lo

I need decompresser valves. I'm pretty sure this will help alleviate/cure my starting problems (unless, of course, you know better).

I've a 96" S+S motor with Edelbrock RPM heads, and plenty of tricky bits 'n bobs inside them. Compression is about 11.5 to 1. Dual Qwiksilver carbs, which issue puffs of vapour (smoke?) sometimes after the engine fails to go over compression and, incidentally, are VERY prone to icing up due to the 14" long manifold.

It's become hard to start. I replaced the battery with a 400 amp (up from 200) to give it some umph. Replaced the under-performing (okay, NON-performing) regulator, upgraded the starter to a Spyke 1.8kw, and STILL it doesn't like to push it over compression.

So I though "I know, decompression vales". Easier said than done. The Edelbrock heads have 12mm sparklers, and the valves I can find are either 14mm or 10mm.

So, does anyone have, or know where I can get, some 12mm decompresser valves?

Thanks

Baff