I had an 85 K10 with a four speed that I junked the 305 and installed
a Vortec engine assembly with a Edelbrock 2116 and a quadrajet
done by Jet. We installed Edelbrock headers and kept the smog pump. The result was very good.....the thing almost zeroed the emissions test plus it
got 10+ in town and 12+ on the road with 3.73 gears and 31 inch tires.
A K10 has too much rotational inertia to ever be a drag racer....especially if it has the granny low 4 speed. However, it can be peppy.

mike in tucson