Does someone know what the LSA spec was for the original Hyper Pack cams? I've searched here and on Google with no luck. Thanks.

I'm no expert on this but I read somewhere that the camshaft in Daytona race version has a lift of .520, duration of 286°, and a centerline of .108. I will check another source a little later when I have access for comparison and/or more specs . But for now this is what I found.
Are you building one?

Chrysler Hyper Pak camshaft part № 2205 620:
276° intake duration
268° exhaust duration
52° overlap
0.430" lift

It has been claimed (without documentary evidence or citations except a note that the claim was made by a "Hyper Pak expert" whose credentials we have no way of assessing) that the Daytona cars used a Racer Brown camshaft with specs of "286° duration" (Intake? Exhaust? Both? Not stated), lift of 0.520", and centreline of 108°. This claim seems dubious to me—the only reason why Hyper Pak kits were available to the public was to qualify them as "stock" parts for the purpose of entering the cars in the '60-'61 NASCAR compact races and other sanctioned events with stock-parts requirements. So the claim amounts to saying they used a non-stock, aftermarket cam in the races that explicitly required stock parts. Does that sound right to you...?

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Too many people who were born on third base actually believe they've hit a triple.

I'm not building a Hyper Pack per se, but I am trying to sort out a dual carb, dual plenum, long runner manifold for my Bonneville car (home made). We've experienced some reversion with it; current cam was LSA 107 degrees. We're thinking that a higher LSA number would minimize the reversion, so we're curious to know what the Mopar engineers used for the Hyper Pack. The best sketchy info I saw seemed to indicate it was 108 degrees, but if anyone knows for sure I'd like to know. Thanks much....

Thanks Dan.

Being a guy that has worked with a few of the hyperpak manifold repop iterations including the fat pack... that is a very common issue... the ram-tuning really likes a tight lobe separation much like the turbo/boost motors....I have used larger cams in the 284/284 range with high static compression, and my last race seasons were done with 2 cams ground the same duration but with different LSA's... 284/284 LSA 111 set at 107 CL, and the last was 284/284 109 LSA and 105 CL...idle was better and seemed to pull better with the 111 LSA... Doc had a post a long while back about the 'sweet spot' for the hyperpak manifold for overlap, the upper end of that is about 55 degrees pending the cam grind...

You might have to grind a couple and do dyno runs to see, what works best for your build... I have a roller cam for next years build to see if that can 'tighten' up the overlap event and work with the hyperpak intake better.

Good luck on getting your car dialed in , every little bit of power helps for what you are doing...

-D.Idiot

107° LSA is about right for a 225, but a 170 should have a wider separation and I came up with 112° LSA after conducting quite a bit of research. The cam I originally came up with for a land speed racing 170 was 248/243° @ .050" tappet lift 282/275° @ .020", 112° centerline and .494/.480" lift. Overlap at advertised duration is 54.5°, at .050" tappet rise it's 21.5°.

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Joshua

Thanks Josh and DI. Josh, that cam you mentioned gave way to the current one with 239/242 @ .050" and LSA 107. It brought me good results in 2013 with the Clifford intake. I also now have an OCG #1694 with 239/247 @ .050" and LSA 114, which was originally intended for the turbo motor now put onto the back burner. From your comments I think I'll go with the latter 114 LSA for the NA dual carb set up.

I would use 112 or thereabouts for a NA 170.

Lou

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Bob,

The engine will make more power with more intake duration than exhaust duration as the intake port is relatively poor compared to the exhaust port.

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Joshua