I understand that the Vortec heads need to be machined to accommodate the LT4 hot cam with 1.6 rockers. I was wondering if the new Comp Cams Beehive spring, from my understanding, does not require the heads to be machined. This set up will be going into a 1992 350 with TPI set up.

 

http://www.sdpc2000.com/htm/vortec_tpi.html

SDPC sells 3 stages of vortec heads with the z28 valve springs capable of some crazy lift right out of the box

Will

 

You might be able to use those springs without enlargening the spring seats (beats me, not familar with those specific springs), but that is only half the problem. You have to cut down the valve guide boss for extra clearance to run increased lift, other wise the bottom of the retainer is going to impact the top of the boss. That sets the lift limit on the stock Vortecs, not so much the springs....

The SDPC modified Vortecs have that clearancing done already. Comp also sells a tool to cut them down yourself, but it also doubles as a spring seat cutter at the same time (you replace the vavle seals too during this mod, they sell those), so you could run regular springs after cutting the stuff yourself, no need for the beehives.

SDPC Upgraded Vortecs