You have the Olds engine and mounts sitting next to the car. I think you've already made up your mind.
Personally the Olds but it's more about the story. I bought a '39 Deluxe with an Olds with 3-2s in about '62 for $350. I pulled it for a SBC. I sold the car but it ended up as a "dirt track" car so it won't be found. I wish I had your luck!
Go with the Olds! I'm looking to put an Olds in a '39 Standard. Are there any threads/stories of people putting an Olds into a '39 Standard? I'm interested in see what they did with the radiator.
i put a 303 olds in my 46 merc 39 trans about 7 years ago, i used hurst motor mounts and offy trans adaptor,mini stater from ross racing,runs like a top and dont miss the flathead...
I had a 1947 Coupe in high school as well. I managed to keep it and finally got through with it in 2018. Thought about the 303 Olds but went with a L3 and automatic. Still have the old motor, mounts adapter 1950 pickup trans with open driveshaft etc but in the end went with current engine. Everytime I look at it I wonder what it would be like if I had kept the old motor. Sure had fun in high school when my buddies had flatheads.