I'm getting close to switching to a roller cam in the big block!

[HawkRod]

Your new springs will be 400# for a few days or running until they settle in to the upper 300s. Unless you really want to upgrade, I suggest you save your money. If you had a race car doing 7000 RPM and your springs were in the 500# range and up I'd worry about it, but for a street car I think you'll be fine.

 

[BSB67]

View attachment 1926914

By looking at the two cams in the attachment, you cannot say which is more aggressive.

Aggressive speaks to the rate that the lifter and valve moves. The contact point between a roller lifter and a roller cam lobe is completely different than the contact point between a FT lifter and FT cam lobe. The contact point effects how the lifter accelerates.

Said differently, if you put a roller lifter on a FT cam lobe, it would move the lifter and valve way slower than a FT lifter on the same lobe. The valve and motor would see it as a smaller cam, and it would make a bunch less power.