magnum r/t springs

K guys,I did my research here and otherwise.

Magnum R/T spring part #: P5249464

This is the lighter one.

This part comes up at Summit as being over $17 each! Emailed them about this as they are supposed to beat any price.

Moparts racing it's about $9 each.

Mancini is about $11 each.

Big difference.Does anyone know the part # for the comparable Comp spring? Price?

Any other springs that will work?

I wont be going over .450 lift. Do I really need to get different springs? I'll probably never see 5500 rpm. Very mild Lunati Voodoo hydraulic cam and stock valvetrain. Mild porting using templates.

The heads have brand new magnum springs (single wound without dampner) meant for a factory roller cam. I dont have a spring checker so I cant tell you anything about installed height or spring rate. Heads are freshly machined. I may need to post pics of the stock ports as I stuck my finger in and cant seem to find that lump for the rocker bolt that everyone bitches about.

Which brings me to another point. Can someone recommend an accurate and economical spring rate checker ?

Also,where (and what)is the factory magnum casting # as opposed to the EQ head?

thanks all!