Go with Vortec heads.

Scoggin-Dickey part number SD8060RA2 is a Vortec that has been modified for extra valve lift and has heavy duty springs to handle big roller cams with lift up to 0.600” (which you may need to reach your target horsepower). List is $399.95 each, but they’ll likely discount a set.

Web site is: http://www.currymotors.gmmotors.com/...ollerCams.aspx

Scoggin Dickey Parts Center
5901 Spur 327
Lubbock, TX 79424

Order - 1-800-456-0211
Tech Info: 1-806-798-4108

These are some real good folks and they love to race the daylights out of anything with wheels.

Good Luck,
Glenn