I think they are stronger spring so that they will recoil faster and the engine can keep up

 

Whenever you do a bigger cam, with a longer duration.. the springs lose time to close the valves, if the spring is too weak the motor would just float out.

A- The valve is opened further, B- the valve is opened longer, so you need a spring that will close it faster... if not you risk the piston hitting the valve. And/Or the motor would just float out at high rpms due to valves being open when they should be closed..the motor will fire in the headers, lose draw ETC.

On very high horsepower motors with big lopey cams, they are forced to use double valve springs.

 

ahhhhh ok makes sense thanks for the clarification lol

 

Valve spring combination is extremely critical for camshaft choice. Camshaft lobe configurations can cause "inadaquate" springs to float the valves and create seat bounce. Also, the springs will float themselves (center of the spring will oscilate towards and away from the valve). On the race car, my valve springs have 95lbs of seat pressure and 210lbs @ .450" lift. This is adaquate for the Crower 280 cams (.422" lift).

 

Check out the difference. Stock on the left High Load springs on the right.
0411001318.jpg

 

Dear God. At installed height you should see a significant gain in seat pressure....lol

 

LOL, Yes Sir. This will take me to 6,500 rpms on my revlimiter. When I switch to the 3" pulley that should put me at 15psi on boost grind 224 cams.

 

Just asking, but have you considered taking the heads to a machine shop and have them verify the valve seat conditions? It may be worth it to just have them do a valve job. Granted, this will have the valves sit higher in the head, but they can grind the stems to get the appropriate installed height (which you may want to consider doing anyway), unless you are measuring these clearances yourself?

 

The clearance is good. Probably next year I'm going to get ported and polished heads and go with bigger valves.

 

That is a much bigger difference than I expected between the two springs, but that's a good thing of course.