M1 SP vs Air Gap

Hysteric said
I know of 1 racer here in OZ who went from an Airgap back to a RPM and lost only a tenth!

Mal. If i were you and you have the LD340 id look to put an open 1 inch spacer and maybe paint the bottom of the manifold with some heat proof paint.

Hysteric

I may not get a 1" spacer under there - but I did find blocking the heat crossover made a suprising difference.

Im not desperate to swap it out - so just trying to find out if anyone has compared the two?