Sounds like a plan.
Have them flattened if necessary.
You mentioned sandblasting them. I am really hesitant and pretty much avoid blasting any internal engine part, the interior of the intake manifold qualifies.
I worked on a very fancy car from the 30's where the previous shop had bead blasted the entire engine inside and out during a rebuild. They seemed to have done a pretty good job overall and I have no doubt that they washed and cleaned it all quite well before assembly. My work involved removing both heads and once removed there were lots of little piles of glass beads in the nooks and crannies, brought by the oil and settled out where it couldn't drain back.
From this (and other's similar accounts) I've learned that no matter how hard you try it is unlikely you can wash and clean and remove blasting grit entirely. It may be partly embedded in the metal surface only to work loose later.
So I don't blast anything where remaining grit could cause harm to the engine.
If there is any gunk or varnish or what have you inside the intake manifold and even if you didn't blast inside it is likely that by blasting outside some grit has gotten trapped inside. Just do what you can to wash and scrub it out.
Grigg
