Originally Posted by Tig
Originally Posted by Dragula
Can you get a plenum spacer from them, or do you need one? Seems all the pics of them, I see one sandwiched in there....And what size carbs for a 512 reving to 6500?

Yep, Indy do them 1/2" part# 440-14-15S $160 according to the price list. I asked Indy about these, they said on a 572 it was worth around 10Hp but only once the rpms exceeded 7200.


With increased RPM and cubes, a motor will want more plenum volume. Biggest thing ive seen is how much it cleans up the air fuels from cylinder to cylinder with proper plenum volume, it no longer has to steal from its neighbour cylinder.