The small block flywheel will bolt to the 454 but unless the 454 is internally balanced (not stock) you will require the counter-weighted 454 flywheel.
I mistakenly installed a 454 flywheel on a small block many moons ago. Made that thing shake like a vibrator.
Thanks for the replies guys. I’ve been working on this engine forever and had to refresh my memory whether internal vs external. Here’s a pic of the “broken” 168t 454 flex plate that I had to replace with the new weighted flex plate. I installed the new flex plate in order to break in engine on a engine test stand. Do you know if there such a thing as a 153t external weighted flywheel from a donar car that would work? I would love to order a billet one from Summit however funds are limited. Any suggestions?