How to make high lift 212cc springs work on a 420cc ?

[212QuickFast724]

i would like to make the springs from the 212cc work on the 420cc because they allow over .400 lift. i ran .360 lift on the 212 and i noticed they only sell valve springs that go to .375 for the 420cc and that just wont work for me.
I guess i could stretch out the 420cc valve springs so the coils are spread further and then insert the 212 springs?
thats what im thinking about doing.

 

[mike97760]

Is there a reason why you cannot run the springs that your cam manufacturer recommends?

 

[IndyHarry]

I think that's open pressure @ .375" lift not max lift like your thinking

 

[212QuickFast724]

Is there a reason why you cannot run the springs that your cam manufacturer recommends?

Noone makes a .460 lift spring like i want and i dont want to run a huge duration so i have less overlap.

 

[flattop1]

At .460 lift you need a spring that will do .500 before coil bind .
A custom spring or one from another application is going too be required .
Jr dragster or motorcycle come too mind still thats a lot of lift .

 

[bpoirier]

You could possibly try try Comp 965-1 valve springs. They are made for Jr. Dragster motors and are good .550 lift.

 

[mike97760]

Noone makes a .460 lift spring like i want and i dont want to run a huge duration so i have less overlap.

What does the cam grinder recommend?

 

[IndyHarry]

With a little work, you could get your intake valve to chase the piston back up the sleeve