MMO and/or ATF in fuel

[Sharps40]

Question time...looking for direct experience.

Problem: Modern high alcohol/low boiling point fuel and carb boil over about 20 minutes after shut down.

Yep, phenolic spacer and heatshield is the best solution for this modern fuel that works well under 35 PSI in EFI but not so much in carbs...but

Marvel Mystery Oil and/or ATF at 8 oz oil per 10 gallons of gasoline is touted as a cure for shut down boil over.

Internet myth or are ya doin it successfully?

If successful, MMO or ATF as your choice of Boiling Point Modifyer?