The carb flange height on this Brodix intake (HV 1800) is 7.38"s high & I need to run a spacer. I think the spacer I got is a 4-hole 1/4" thick. The main problem while I was mocking up the ProCharger was the amount I had to rotate the volute. Plus, I don't like how one of the volute securing brackets would need to be modified.

Anyway, while this manifold worked well. I never did like the height of it. I know 1" can be milled off & maybe 1.5"s, before it gets into the extended runners. Anything else I should be concerned with?

Aside from milling it correctly the only thing else you will have to do is tap the carb mounting holes a bit deeper.
I've milled three different manifolds so far and they all seem to perform better, go figure

I milled intake carb flanges many times to get rid of the wedge angle often cast in on some intakes....

Flycut it and then redrill and tap the mounting holes deeper and straight.

I Never cut a ton off like your wanting to do but as long as you have enough material there to be able to do it and still have mounting holes and don't create any thin areas or break thru.....it's doable...

Once had a shop send me a set of Olds heads and he wanted to mill the rocker stud pads .300" Iron heads....

Set it up and started cutting.....slow process with a single flycutter in a Bridgeport. Would have been better with a big multi cutter carbide tool but we did not have one..

Broke into water jacket after a while.....head was now junk

Other shop guy said why didn't I stop ! Well you said mill .300" off there and I assumed he knew it could be done.....NOOOOO it can't !

You can't put metal back unless it's aluminum........and that's not something you want to have to do unless it's a must....and you have the equipment and skills to do it...

Looking at that intake I don't see much of a problem. They have cast bosses in for the bolt holes. I would attack that one in a heartbeat but I have all the machinery and can weld it back if needed.

just wondering why a spacer

Thanks for the replies. Machine shop stated it shouldn't be an issue.

As for the spacer 1/4" 4 hole spacer, the Holley Sniper seems to cause a loud whistle without one. Not that it will be heard over the ProCharger, but I want to isolate some heat from the throttle body anyway.

Some shots of the plenum/port dividers on the manifold. If I remember right, there was about 1.5" to the top of the port divider. I will have the divider reshaped if needed. Regardless, the pad is getting cut minimum 1". Just for info these are raised runner ports.