If the springs are the Indy G928's, that's a completely different spring.
When they stopped using Comp springs, I remember there was a period of time when you didn't really know exactly what you'd get when you ordered them with the "928" springs.
Most of the time though, they were a pretty high rate spring that would be over 400lbs @.650 lift if installed at 1.900.
I would have expected the motor to peak closer to 6700 if the valvetrain was rock solid, and would have likely only been down a few hp @7k....... But that assumes you had pretty stout springs in it.
And, that's also assuming the intake behaved similarly to the 440-2 in the upper rpm's.
Before I messed with the installed height, I'd find out what the open pressure is now.
If its already in the 400lb range....... I'd probably just live with it for a street application.
The cylinder head guys sheet says. The springs on the intake are 150 open and 360 lbs at .600 lift and 400 lbs at .700. .110 to coil bind.
The sheet on the exhaust says 160 seated and 380 at .620 lift. Coild bind at .775 lift. So they must be the comp springs. Not sure why they're worded differently. Seems the .025" installed height gives a decent amount more load. My curiosity is: Shouldn't the heavier intakes need a bit more than the exhaust if you wanted them different? Or is there a reason to have more spring on exhaust?
I'm happy as it is. I feel if I were to want too much more pressure then I would just move to a solid roller and maybe a external oil line lol.
