Anyone use a Demon Carb

Yes, They are very good at what they do.

But...

I've found issues with metal shavings and flash in the metering blocks, and they can be set very close to perfect. So close in fact that around me, if I set one perfect in the mid day heat, when the sun goes down, the tune will be off. And then I change it to be perfect in the cooler air, it runs way different when it gets hot. I havent messed with air bleed sizes yet on the troublesome one, I'll do that when this particular car returns this spring. I'm thinking the main bleeds are too large. This is an Indy supplied 750. Others I've seen have had metal issues, but ran decently after "cleaning them out".