To roller rocker or not to roller rocker? ratio?

[turbo96max]

Buick fam,

When do rollers become a must have ? due to budget im considering the ta hd shafts vs roller.....

if its a must do, what is most recommended for this setup as far as Rocker ratio?

champion handported irons (setup w beehive springs for roller)
215/210 comp cam
something similar to 6466 range turbo (probably a 4bolt custom unit)
25 psi
girdle, forged rods, steel crank, steel rods
ta neutral balancer

 

[fastblackracing]

Increased rpm, improper tightening procedures and the required extra spring pressure to run more aggressive cams are the enemy of stock rocker shafts, they seem to handle the extra lift pretty well since we typically do not run real hi-lift cams compared to say a v8 set-up. Way back in the earlier T/R days before after market HD shafts were available I went low 10's with stock shafts that I modified by machining a steel slug about 3 inches long and pressing into the hollow ends of the shafts and then re-drilling the bolt holes, and also made steel shaft supports that looked like tiny main bearing caps......this was done using The first design 206/206 roller and comp 941 springs....... so yes The hd shafts and supports that are available today will work fine as long as you have the propper length bolts and they are not over tightened and crack the shafts.......FYI....when I was making the modified shaft deal I first measured the deflection of the stock shaft, the overhung portion at the ends, rotating the engine thru the lift cycle and saw .006" when at max lift/open spring pressure,and after putting the modified deal on it measured .0015-.002......this was done on the engine stand, can you imagine what was going on at 6000 rpm?