I'm running 3/8th stud 1.6 S/A crane rockers with the crane 99893 springs, shifting at 6500. Should I upgrade to 7/16 studs and NSA rockers, or should I be ok with this? If I upgrade I'm thinking about the comp 1.7 rockers, so I gain some power with the switch...

 

Sounds fine to me. Although, Im wondering if that cam peaks at 6500. I think you would be fine shifting at 6200.

 

Look at his sig. GM846 = not stock cam

 

846 probably peaks near 5500 5400 id spin it to 6400

 

Don't think ya got enough installed height for 1.7's.
The 3/8" studs are fine unless ya are running WAY more spring pressure than I would.

 

it takes alot to bend or break 3/8's studs if your really that worried about them order a set of arp's and some stud girdels

 

If you want to upgrade things, try the 918 beehives with titanium
retainers. You can also use the +.050 super locks to increase the
installed height a bit.

If you do not have the L98 spring seats on your current setup, I
hear they work great with the Crane 99893 springs. The shims that
are normally used with the Crane spring kit are not so good. If you
have had the 99893s on for quite a while it may be time for new
springs anyway.

 

I just put in new crane springs a couple months ago with comp seats, locks, and retainers... And the power stays flat till 6400 where it dropped off like 5rwhp, then the dyno stopped reading the tach signal, so I picked 6500 for the shift point. http://www.lifeinwidescreen.com/siihp/846_dyno.jpg