Sorry, I did not read page 2 stating 977 springs.

Here are the advertise spec on the Comp springs;

Comp 977's: dual spring (requires machining of spring pockets in a stock head)
O.D: 1.46
I.D: .700
seat pressure: 155 @ 1.850
open pressure: 419 @ 1.250
coil bind: 1.195
spring rate: 441

Comp 921’s:
O.D: 1.300
I.D: .870 (outer spring)
I.D: .655 (inner spring)
135 LBS @ 1.770
400 LBS @ 1.220
COIL BIND @ 1.040
MAX LIFT .650

Not sure with the added valve and pushrod weight if the 921 will do the job.
With the additional seat and .600 pressure needed to control this heavier valve train, may also need upgraded lifters.
Bob

 

I've decided to just shim the 977s and see how that works.

 

You may want to remove the spring and check the install height. Then check what the seat and .600 pressures are. Then compress the spring to coil bind and get a measurement of actual coil bind.
Typically, hydraulics like to be shimmed to .050 from actual coil bind. But I am not sure how much seat pressure that will give you.
What lifers are you using?
What tool are you going to use to remove the springs?
Keep us update on how it goes.

 

The weight on the pushrod side isn't near as concerning as the valve side. The spring is trying to control the valve. The bigger intake valve coupled with a max lift camshaft might be putting you just over the limitations of the springs. Yu deffinatlly need to check the installed height, then go from there with your shimming.

 

I'm using stock lifters. Thanks for all of the input and I'll keep you updated with my progress.

 

Mike the car sounds sick. Cant even tell you have a cam. I would never see you coming on the street. Mine is twice as intimidating and slower.... dammit.

 

I wanted to run you after you were done with the dyno but I got caught up talking to Brian (the guy with the yellow Trans Am). I have the ported throttle body on now and it makes a huge difference in throttle response. It feels snappy like a h/c car should.