OK. NEW UPDATE.
Found details on the springs I believe are on the built '69 heads.
The other engine had Performer RPM cam and intake, and I believe Edelbrock springs to match the cam.
Edelbrock Part number 5722 - which is recommended for ALL YEARS.
Single spring per valve.
110-120lbs seat pressure
1.77" spring height
1.140 coil bind height
I get .630" lift to coil bind
.630" - .542" = .088" from coil bind
I'm thinking the springs that are already installed on the heads will work just fine.
The only difference between the roller and non-roller RPM kits is the cam and lifters. Springs are identical.
It supports a performer rpm cam at .520 max lift on exhaust side, .542 is so dang close (AND with LESS duration) I think it will be ok, what do you think?
Plus, they are ready to run as they sit!
Tried to find the spring rate but no bueno!! Not a lick of information anywhere on spring rates and I searched for a while.
Unless you know who makes Edelbrock 5722 springs, or a part number interchange I don't think we'll know the spring rate.
I want to run what works, and will be reliable. Won't too much spring tear up the valvetrain and cause my exhaust valves to recess into the seats?