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There are three different things going on here.
First, the Comp Thumpr cams came out at least 6 months before Hughes' Whiplash. I believe that the Whiplash was a response to the Thumpr and in typical Hughes fashion they did it just a little better. As you yourself noted the Hughes "real Chrysler" cam has more lift per degree of duration. It sounds like the Comp is one more Chevy lobe on a whatever core.



There are actually three different cams noted in this thread too though... The Thump'r, Hughes, and the Comp 'Mopar lobe' XE/HL cams. The Thump'r still seems to use the old Chevy style lobes, i had no interest at all in those, they were just mentioned.



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Also, the quicker rate of lift for larger diameter lifters is not a Hughes secret, it's an early Machine Design principle. So to say that the Comp is in any way a ripoff of Hughes is laughable. It just took Comp a little longer to see the market for the lobe, they probably let Hughes do their market research for them. Again, this is common in the competitive world of industry.



Yeah, i think Ultradyne was doing it before either ov them?

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Okay, now on to second point, you may have old springs where the part number stayed the same but the spring itself was changed slightly (upgraded) over the years. So I'd believe what's on the box they came in. And yes, springs are blessedly linear and your math looks right.
Third, I am about as cheap as they come and the more I think about this the more I think you will be all right without spending the extra $$$$. Keep in mind to break the cam in to Hughes specs, including removing the inner springs. Then be careful in the upper rpm ranges where the springs might possibly allow valve float or bounce earlier than a stiffer spring.
As for the lifters, they all come from just a couple of places, as long as the oil doesn't come squirting out around the lifter it should be OK.

Keep us posted on your results...
R.



Someone locally said the same thing, i was just comparing the spring rates on the box they came in with the rates in the catalog... which i got around the same time i got the springs. Its a 2002 catalog, which is when i bought all that stuff.

Anyways, if there is nothing weird i need to know about the math (linear, as you said), then i can probably figure this out from here. I am looking forward to buzzing this thing... so i hope i dont screw myself being cheap. But the whole concept is temporary... while i get this car's real engine sorted out. This will keep me on the road for a year or so hopefully.

Thanks.