Is there an advantage to running a larger diameter vavle spring? Say a 1.55 vs 1.46? Also how are the Comp R lifters better then the regular magnum lifters?

Thanks
Jeremy

 

A larger diameter spring will be able to have more total wire at a given height, increasing the spring's abilities. There's no specific "advantage" to them other than when running a cam large enough to need more spring presure. You shouldn't run much more spring than you need.

The "R" lifters supposedly are able to run better at high RPMs because they have an anti pump-up design.
FWIW I had a Comp R lifter come apart on me and f*** up my engine.

 

Just put long tubes and a cam in your car and lets run 'em!

 

Also, for a given seat pressure, open pressure, and lift, a bigger-diameter spring should be more durable.