theres a difference in the weight of the valves, but it isnt much, i think its like 4 grams on one valve and 7 grams on the other... you probably couldnt tell if you holding them..
you could negate the weight with stainless undercut valves if its that big of a deal, a set of stainleess undercut valves costs about $90...

the lunati springs i listed above have a 108lb seat pressure at install height, its the spring that lunati recommends for thier lt1 cams up to like .560 lift..

 

GM puts an LT1 throttle body on the Ramjet 502, does that mean it is right????
GM put a zinc aux. battery terminal in the 94 and early 95 b-bodies that overheated and melted fuse boxes in some cases burning cars to the ground, is that right???

GM did do a lot of things well but not everything so the BLIND faith placed in them for using whatever spring they had in inventory is missplaced.

 

Post a link to a single case of failed springs in a properly installed LT4 hot cam kit using LT1 valves.

Or to a single dyno sheet showing valve float in the operating range of an LT4 cam with a properly installed LT4 hot cam kit using LT1 valves.

Better yet, lets see the spintron data you have to back up your claim.

 

I never said they would break springs, beyond that, whatever, believe what you want.

I didn't put together what I have by not knowing what I am talking about.

 

Valve weights for LT1 versus LT4:
Exhaust 97g LT1, 75g LT4
Intake 110g LT1, 85g LT4

(Did not mean to imply the LT4 springs were bad, they just do not increase open pressures beyond the LT1 springs, so are not a want higher rpm solution. In both lift and seat bounce they are better than LT1.)