[beerslob]

hi , i have a pontiac 400 with 1968 16 heads stainless replacement valves 5.90 i got a summit 2802 cam 466/488 298/303 they sold me comp cam 995 springs . would this be the best springs to use with that cam? thanks for any advice...tony

[steve25]

Well they will work with some work!

Your installed height now with a freshen up valve job and those valves is around 1.60”
Those 995 springs will have 115 pounds on the seat at a 1.700” installed height according to Comp Cams spec.

Since it looks like your running a install height that is .100” shorter you going to need to get the spring seats cut some.
You might call Comp cams to see if they offer a retainer that has a .050” higher keeper location, then you would just need to cut about .050” off the spring seat in the head.
Spring pressure seat wise you want 125 for the intakes and like 120 for the exh valves.

If you want the best current spring set up and you can send those springs back then going over to Beehive springs along with the needed new small retainers is the modern way to fly!

This set up cost more but they need less seat pressure for less worry during cam break in , yet they will run to a higher rpm then classic springs, while having better dynamic control throughout the Cams rev range !

Oh, sorry I missed your pm the other day!

[Cliff R]

The last set I had in here supplied by the customer for his KRE heads at 1.7" installed height checked at 160lbs on the seat and up near 400 lbs over the nose from what I can remember. I decided not to use them as I'm not a big fan of a lot of spring pressure on these engines especially with flat cams in them.......

[steve25]

Cliff it sounds like the springs for that build that you got handed where boxed wrong, and where really a 950 set of Comp springs.

This set is the same duel spring and flat wire damper set up as the 995s and have a pretty close OD of 1.45, they however have 145 pounds on the seat @ 1.700”.

[Steve C.]

Comp 988 rated 117 @ 1.600" ?


.

[steve25]

In my comp catalog those 988s are stated as 110 at 1.65” so yes the can work , but they are only stated for use with there 268H cam or less, plus once shimmed to a workable installed height would only be good to .500” lift.
Even with that you would still not have the needed open pressure for running cams above the 268H cams spec’s.

[Steve C.]

I was using the information here:

https://www.compcams.com/valve-spring-chart

And as repeated so many times... NEVER trust catalog published specifications since they can and often vary.
Measure them with the proposed retainers in place at the actual verified installed height.

.

[Jay S]

You already have the 995s, which will run ok if they are set up correctly. But IMHO, with the 1.5s and the stock installed ht the 988s would have been better. The 988s get ran on the 224/236@.050 hft cam from CRANE frequently, and it is more aggressive than a 2802 summit. IRC, in the comp catelog they jump from a 988 on the XE262 to a 995 on the XE 268. Lol. 100+lbs change in the spring rate for 6* jump in the cam. Pretty obvious the comp has a one size fits all approach in the catalog.

[KEN CROCIE]

the comp 988 is the same spring as my old VS-11. Best spring out there for stock installed height. Will work good up to 6K rpm with a HC-02 type cam-232/244 @ .050" and is easy on the lobes.
inst. ht seat .450 .500
1.590 120# 254# 267#
fits stock heads with no cutting, can use stock retainers .
dual spring, interference fit, no damper

[Cliff R]

Good info Ken.

The 995's that I checked were a double spring with an inner dampner that needed the sharp edge smoothed or it would have cut into the shims/heads.

I remember one of the springs being blue in color, same as pictures I've seen of them. They came with retainers with a pretty deep inner step but I couldn't see that alone making the pressures that high........

[beerslob]

ok thanks for the info