I`m sorry,the part # is 96872,they recommended the 99893 springs for my cam but I believe they are a little to stiff.I need to call their tech dept to make sure the 872s are OK,but I don`t see a problem w/ a lighter valve train & I`m going to keep the mtr. under 7000.The 872s have a little more seat pressure,but less open pressure,which should make more power as the engine turns over easier.With my 550 in & 570 ex lift I`ll still be over 300 open.They kinda contradict themselves a little when they say not to run over 330lbs open pressure on a flat tappet cam like mine,& then recommend the 893s for my cam which puts it over that thresh hold.they say this will cause excessive cam wear,go figure.:confused:
Depending on what rpm range the roller cam in this motor is design for?.. I would be VERY careful with beehive springs. Don't ask me how I know.. but running single springs without an inner damper puts you at severe risk if you ever break a spring. Because of that little fact.. beehives have NO MARGIN for reducing major engine damage if a spring lets go. Ask any LS guy about these springs and he'll have stories to share. Polished versions have greater fatigue life but the cost goes up quickly. Another rule of thumb with rollers is that they generally require about 10% more seat pressure than flat tappet cams rated at the same exact rpm range. This is because of the inherently faster ramp rates and the extra stress it imposes on valve control going onto and coming back off of the seats. For that reason.. it's sometimes best to buy the extended lift range versions that handle .650 lift cams and then shim them up a bit for greater seat pressure/valve control. And you do realize that beehive springs take specifically sized retainers too, right?
You need more seat pressure w/ rollers because they are heavy & have to be controlled to keep them on the cam.
unless you have $700-1,500 worth of lighweight lifters to help counteract the valve loft and overall loss of control. Then maybe throw on some Ti retainers and/or valves and just.. fuggedaboutit. lol 150 -220'ish seat is pretty average for most hot street motors running stouter hydro rollers round my neighborhood. After that.. you just bite the bullet to run solids and maintain your setup. I don't want to start a controversial thread here.. but there have been many, including some cam grinders, who've successfully run solid roller lifters on hydros in recent years past. You'll never get the full effect from the hydro ramps not being perfectly suited for the solid roller tappets greatest benefit of being light.. but you're rpm potential will definately go up. The best thing I've heard is that it helps to measurably reduce spring requirements. Less spring with better control wins it every time. They help an engine last longer too.
