I cant seem to find out the info needed for my springs. Maybe you guys can help or steer me in the right direction. I have my vortec heads in the shop and am having them modifided to run an lt4 hotcam. The shop needs to know what the installed height of the springs is supposed to be and the seat pressure. Anyone know what this is or where to find out?

Thanks
mavis_1

 

Would that be GMPP valve spring kit 12495494 (16 PCs of 12551483) ??

If so, the design installed height is 1.782". At that height, the seat pressure is 102#. Coil interference (bind) occurs at 1.220", which only gives you 0.560" of lift to the point of damage, and in reality only about 0.540 of safe lift. If you already have them, and can't send them back, use them carefully. If not, you may want to consider a different spring more suited to the use you intend.

Oddly, however, that GM stated using this "ovate" wire on the LT4 springs over ten years ago, and now similar springs are offered in the aftermarket. Was the factory the leader on this one? Could be. That would be a little different that usual.

 

Why would he not use the LT4 springs when he said hes running the LT4 hot cam? I have LT4 springs with a cam thats not even intended for them and havent had any troubles in over 2 years.... No signs of float at any RPM's and the cars run better than anyone I know has ever said it would.

 

I didn't say they won't work. I have set myself. They work fine. All I wrote was that there are better srpings out there. I keep the LT1 in Mrs. Vader's "beater" under 6,800 RPM just for that reason. I used the LT4 titanium retainers and keepers, too. No problems here either. Still, if he plans on some real revving, larger and higher pressure springs would be safer.