some 3k's wont have the oulets nor "plumbing" for the EGR. so they WILL bolt up. just depends what engine each manifold is from.
I know of 3 different exhaust manifolds, there may be more?
1 i had on my ke25. single outlet, 2 bolt flange ( not the best option in my opinion)
the 1 i have on my ke30 2 small outlets. Bolts to a twin pipe that merges into 1. kinda like 4-2-1 style extractors.
And the one i have off the 2 ke70 4k's i have had. single outlet. bigger that the one i had on my ke25.
I myself would run with the 3-2-1 manifolds.