Valve spring delima !

I feel like I have talked with several reputable engine builders about this particular situation that has me confused!

I have a small block stroked to a 408 13.0:1 compression.

8000 RPM

Cam is a solid roller with

Lift
Intake .688 exhausted .672
Duration @.050
Intake 276 exhaust 284
Lobe seperation 107
Installed @103
Some more info :
Lobe lift
Intake .4300 exhaust .4200
Timing events intake op 35 cl 61  exhaust op 73 cl 31

1.6 rocker ratio

Spring psi that cam company wants me to run is
250+ on seat
780 open
Installed @ 1.90

What do you guys suggest ?

Thanks Whitefield

whitefield wrote:I feel like I have talked with several reputable engine builders about this particular situation that has me confused!

I have a small block stroked to a 408 13.0:1 compression.

8000 RPM

Cam is a solid roller with

Lift
Intake .694 exhausted .698
Duration @.050
Intake 268 exhaust 274
Lobe seperation 107
Installed @103

Spring psi that cam company wants me to run is
250+ on seat
780 open
Installed @ 1.90

What do you guys suggest ?

Thanks Whitefield

I don't know much but that seems way to high on the open pressure to me!!!

A lot of it depends on the ramp rates. Some solid rollers will whack a valve open faster than the speed of light!!
Lobes like that need big spring pressures. Other lobes are more forgiving and you can back the pressures off a bit.
Are you experiencing valve float or broken springs??

you building a race car or a street car?

What's the installed height? Lobe lift? Rocker ratio? Spring rate?

Who's lobes and what numbers?

And just for the record those are not super big springs.



But I do suggest listening to the cam manufacture over soliciting online random suggestions.

dfree383 wrote:you building a race car or a street car?

What's the installed height? Lobe lift? Rocker ratio? Spring rate?

Who's lobes and what numbers?

And just for the record those are not super big springs.



But I do suggest listening to the cam manufacture over soliciting online random suggestions.

It is a race car
Bullet racing cam
Installed 1.900
1.6 shaft mounted rocker arms
3/8 .080 push rods
Spring rate 644lbs./in.

I will get the rest of the info in a few minutes.

I agree with your last statement, but there are a lot of good experienced people on this forum. I am not on any other forums anymore this one is home. Thanks

P.s. The other reason I was confused is I was getting two different answers from two different people from bullet.

I added some more info about cam and changed some things I had wrong in first post.

PAC-1225 was the spring they recommended. Thanks Whitefield

whitefield wrote:

dfree383 wrote:you building a race car or a street car?

What's the installed height? Lobe lift? Rocker ratio? Spring rate?

Who's lobes and what numbers?

And just for the record those are not super big springs.



But I do suggest listening to the cam manufacture over soliciting online random suggestions.

It is a race car
Bullet racing cam
Installed 1.900
1.6 shaft mounted rocker arms
3/8 .080 push rods
Spring rate 644lbs./in.

I will get the rest of the info in a few minutes.

I agree with your last statement, but there are a lot of good experienced people on this forum. I am not on any other forums anymore this one is home. Thanks

P.s. The other reason I was confused is I was getting two different answers from two different people from bullet.

Either Spring Randy suggested would work IMO.