I haven't, I've had big blocks my whole life.
Have 360 in my 73W 200, it isn't a powerhouse. 383 would be better. imo
To be honest I never had or drove a 340 powered Mopar.
I did have a few early slant six Darts as parts runners, excellent fuel mileage , but boring. lol
My brother did the 440 swap to a 64 Dart in the early 80's.
You do know I'm just :poke:I have very limited experience with the small block.
I have to admit, I'm impressed with some of the #'s guys are running with the small block platform.