oOoLy

what is the best spring for my cam (cam lift 632 intake, 646 exhaust) ?

I have Comp 978 Spring, so I must change it or it will be ok ? I heard the some people has some troubles with theme ?

Thanks
Adnan

94form2000z

iTrader: (10)

I would change. I don't believe those are spec'd to handle that lift.

mrr23

iTrader: (3)

http://compcams.com/Technical/Curren...ML/324-339.asp they are listed in the dual spring section. it's not even listed in the Gen III section. even so, their current LS1 springs are rated for .600" lift.

http://compcams.com/Technical/Curren...ML/340-349.asp on this page here it lists the max lift to be .600"

here's a spring you can use that will support up to .650 lift and fit the stock head pockets. http://vincihighperformance.com/2004...LE%20PAGE.HTML currently on sale at vinci.

SouthFL.02.SS

The how does TEA set up the 987 springs on their heads good up to .610-.620 lift?

mrr23

iTrader: (3)

let me restate. the max recommended lift is .600" on that chart by comp cams. you can change the max lift by changing the installed height. if you install the springs taller than recommmended, then you can increase the amount of lift before coil bind. recommended installed height is 1.850. move it up to 1.900 and you've just gained .050 more area to add lift. the only thing is how much pressure loss by raising the spring up did you lose? using their chart, at 1.900 it's 107lbs. at 1.850 its 127lbs.

94form2000z

iTrader: (10)

Well I've been using the 987's setup on my AS heads @ 1.850 for about 20k now with a .588 lift cam. Works great. No float or any other problems. I think I'll just stay with what I got but refresh the springs.

mrr23

iTrader: (3)

because you are under the .600" lift recommendation, you are fine and don't need a stronger spring. he has lifts in excess of .600". so a different spring is in order.

94form2000z

iTrader: (10)

Oh I whole heartedly agree he needs alot better spring with that cam.

Actually if you look at Comps chart is shows a recommended lift of .500 on the 987's For some reason I find that chart to be under rated.

mrr23

iTrader: (3)

yeah, i saw that and went HUH???