Probably not, Nvidia has never allowed different GPUs to SLI, even when they are the same die. They had to have the same GPU, memory, and core count.
The only oddity I can think of was something like the 650Ti Boost and the 560 Ti, different branding, but the exact same GPU. It really didn't come up too often.
AMD was more lenient and let the same GPUs operate in Crossfire, but the larger card would be reduced to the lower core count.
SLI isn't really worth it anyway. Sell and replace with a 2080Ti. Then if you need more power at that point, consider 2080Ti SLI. Sadly monitors have outpaced GPUs for the first time in a while.