I just looked again at CL nationwide......there are Vortecs for 150.....

BEWARE Real "Vortec" heads are easily identified....they have only four intake mounting bolts per head. They have center bolt valve covers ONLY. Vortec heads were put on 96-2001 GM 350 engines installed in trucks and vans. Vortec heads are the best flowing stock GM heads that will fit a small block. The intake gaskets are unique to Vortecs.

A vortec head will require a vortec intake manifold such as an Edelbrock 2106.....inexpensive manifold. The heads also require the proper guided rocker arm.