Okay, this is where i get confused...

I looked up the Comp Thump'r, there are 3, from a 227/241 to a 235/249 to the big 243/257. The Whiplash is 232/245, yet it has more lift than the biggest Thump'r. Is it the lift, or the duration/ramp profile that dictates the spring needs? The Comp Cams springs recommended are close to what i have. The 995-16 spring (recommended for all 3 Thump'r's), which has the same seat and .550" rates as mine, but an extra 50lbs rated 'rate'.

I assume the Comp is using a less aggressive ramp than the Hughes? Is that why i need more seat pressure?

One more thing. On my box i have right here, the 924-16 spring is rated at 297lbs, yet i just looked on Comp's site and there its rated 347lbs. Which is which? The spring is stronger than i thought it was. Or did they change the specs in the 10 years since i bought these?