We have many heads for Chevy Inline 6 in stock. The choices can be confusing. Factors to consider when choosing one of our heads.
1. Size of engine  Bigger cubes can work better with larger valves. Stock Intake valves are 1.72, we upgrade to 1.84 or 1.94
2. Intended use of engine Casual cruiser 1.84, hotter engines 1.94
3. Cam lift and intended RPM.  Our .530 lift spring works great with lower lifts such as .530 LIFT OR LESS stock, RV or Performance CAMS. RPM limit can vary depending on duration of cam and the lift. 5-5.5K RPM  Higher RPM  if less lift is used with a large duration cam. The .600 spring can rev even higher with smaller lift cams. We can equip our heads with any spring required for your service.
4. Intended compression ratio desired. There are many CR calculators on the web. Learn to use one. Most of our cams like 9-10.5 CR
So we offer a variety of CC chambers.
5.Roller rocker are suggested when lift exceeds .500
Some people notice the tiger striping on our heads. These are surfaced on a CNC machine instead of a dedicated head surfacer. The dedicated machines tilt the cutting head by .004" to only cut on the leading edge (like a lawn mower). The CNC has a perfectly aligned cutter head and will leave a trailing mark, such as seen on these. Rest assured these are perfectly flat and you cannot "feel" or measure and deviation from flat.