u/Bleak-Horizons

I am adding flood vents to an existing crawl space. I removed the block 8x16 from the wall and was planing on installing the vent as is but was wondering do I need to support the load above.

The vent opening has two coarses of block above it a wood plate and then framing. The floor is not supported on this wall but the roof load is.

Can I insert 1/4 flat steel over the 16in opening or do I need angle iron. If so what size?

Thanks in advance for any input