Phenolic spacer on a factory manifold

Here's another question.  I was thinking of putting a 1/2" phenolic spacer under my Holley to help insulate it from the manifold.  On the Summit website it says "not for factory manifolds with an exhaust crossover".  I guess it would melt the phenolic.  What if I put those metal blocking plates in the intake manifold gaskets?  I already have my heat riser wired open.  Would that be enough to keep the phenolic from melting? 

A guy on the corvette forum said that an Edlebrock wooden spacer would work.  His company makes them for Edelbrock and he says they can take the heat.

Que?

Blocking the heat riser passages in the manifold gaskets would work.....might create longer warm-up time, but here in Texas, that's not really an issue. I think the real problem would be the EGR passage, as it runs under the carb base gasket....
I'd be concerned about hood clearance, also....is a 1/2" rise in carb height gunna fit under the hood without interference? Might be a little tight...

|UPDATED|8/15/2014 4:25:12 AM (AZT)|/UPDATED|

I got an LT-1 (no EGR).    I stuck some clay on the air cleaner and I have just under an inch of clearance.