Stuck carb adjusting screws

[Tilar]

I'm working on a thermoquad off of a 73 with a 400. The throttle shaft was froze when I got the car. I've had a ton of experience with regular frozen bolts and removing broken bolts, Hell 9 times out of 10 I can take a torch and cut a rusted nut off of a bolt and still be able to use the bolt. Overall success rate is probably in the 90% or better range.... UNTIL I came across this damn carburetor.

I got the throttle shaft and the secondary shaft freed up, Twisted two screws when removing the butterflies but got them drilled out and saved the shaft, However the two mixture adjusting screws in the bottom plate are froze up. I've done everything I can think of short of adding heat to them and I really don't want to do that with an aluminum base plate. 

I tried looking for another carb but no luck. I have one off of a later year 440 which is what I put on the car to get it running, but I'd like to use what was meant to be on it, Plus the air cleaner that came with the car won't fit.

Does anyone have any suggestions?

[beedees]

I've had fairly good luck using a mixture of acetone and ATF and a LITTLE bit of heat. Don't get in a hurry.. Good luck

[Tilar]

I was afraid to try any heat around the aluminum base. I bought some penetrating oil called "Free All" that really loosened up the secondaries nice and I've been soaking the mixture screws every day for the last week. I've tried shocking them with a small hammer, Had it clamped in a vice with vice grips clamped onto the screws acting as a weight hoping that would loosen them up. I finally got to the point today that they were either going to break off or move, and they broke off.      I just finished ordering another base plate from some carb rebuilding place out of California. That will still get me a rebuilt carb for less than $125.

[Chryco Psycho]

some heat & run some wax down the screws