I am putting an lt1 cam in my 305 TPI with lb9 heads from an 87 IROC when i search for springs I need to know the outside diameter of outer spring, the installed height, the seat pressure at installed height, the coil bind height, the open height , the open pressure, and the spring rate. They are for the stock heads so i have to make sure they will work on the heads the cam should be fine for the stock size i just want some new ones that arent worn out. Can anyone help me out.

 

comp cams 981-16

 

They are 1.25" diameter single coil springs with a dampener coil inside.

Let me save you a lot of trouble..... factory LT1 cams used absolutely nothing special as far as springs go. They are virtually identical to the springs that TPI heads came with. And they aren't all that good. They rely on the cam lobes being really "lazy" to work in the upper RPMs. LT1 cams were the first ones that GM started to actually build a bit of aggression into the lift curve. They went to about the limit of what stock springs can handle at 5500 RPMs. If you have the funds for a simple upgrade, please consider upgrading them. And on that note......

I have used Comp 981 springs as drop-in upgrades for stock springs many times. Even with mild factory hydro roller cams like the LT1. They are about 105# on the seat, 1.70" installed height (stock) and have a rate around..... eh, I recall about 280 lbs/in. Max lift is stated to be .470" but is, in reality, more like .500" starting from a 1.70" installed height. Still, more than enough with your LT1 cam's ~.450" lift.

You can reuse all your factory valvetrain gear- the retainers (even the exhaust-side rotator retainers), locks, valves, etc. They are literally drop-in upgrades.

Factory springs, for comparison, are about 70# on the seat @1.70" installed height, and about 220 lbs/in. spring rate. So you can see the Comp 981s are considerably stronger than stock.

Option #2..... cheap eBay "Z28" springs. Similar specs to the Comp 981 springs but dirt cheap. Also drop-in simple.