These look decent and comes with the collectors for $225.
https://www.summitracing.com/parts/p...make/chevrolet
Summit has 2 sets of their brand of exhaust manifolds for around $220.
Here's a list of exhaust manifolds on Summit's site for LS motors.
https://www.summitracing.com/search/...rder=Ascending
Also read some of the reviews, since some of them mention C10s.