Snake Skinner

So if I decided to keep the hotcam and go with either the SLP or Crane 1.8's what would the hotcams lift be? Also with stock valved heads milled .035" would there be any P/V Clearance problems? What springs would I need to go with?

SSINFUL

The Cranes are a true roller rocker. The SLPs are a roller tip. Not a huge difference in performance, but a small difference in quality.

I have the Cranes w/ a .528/.539 cam (218/224 @ 112). W/ my '98 there were clearance issues w/ the valve covers, but a little sanding/grinding here and there = no prob. 1.8 vs 1.7 = .0588% more lift. So, the HC w/ its .525/.525 would be 1.0558 x .525 = .556 in and out. Not huge by 2002 LS1 lift standards. 3 or 4 years ago, people would have about freaked w/ those lift #'s. Now, folks are doing .600.

Also, 1.8's change yer duration #'s, too. They alter what the cam is doing at high lift. The valves stay open longer at .400 or .500 lift, which (should) gives more hp!

I am running the 918s. This is my second cam using the 1.8's. Before, I had the 941s. Never had a problem w/ valvesprings.

ls1290

iTrader: (20)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by SSINFUL:
<strong>Also, 1.8's change yer duration #'s, too. They alter what the cam is doing at high lift. The valves stay open longer at .400 or .500 lift, which (should) gives more hp!
</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Really? I thought that they did not affect the duration at all, just the amount of lift. Anyone else confirm this......

Chris Spiess

yes, it's true. Since the rocker ratio is a multiplier of the cam lobe you get to partial lift number sooner on the way up and later on the way back down. The amount of the duration change will be a function of the cam lobe profile - more aggressive lobes will see less duration augmentation with higher ratio rockers than more mild profiles.

<small>[ September 23, 2002, 09:16 AM: Message edited by: Chris Spiess ]</small>

ls1290

iTrader: (20)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Chris Spiess:
<strong>more aggressive lobes will see less duration augmentation with higher ratio rockers than more mild profiles.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">What do you thing the affect of 1.8 rocker arms on a 236/236//591/591/112 cam would be?

SSINFUL

ls1290: You can't put the 1.8's on that aggressive of a cam (ramp rates). Nothing more than (maybe) .545/.545, and even that would be pushing it...

The components wouldn't be able to stay in contact (valve float- interference)