ls1290

iTrader: (20)

Woul done expect to see about 10% increase in lift from changing stock 1.7 rocker arms to 1.8 rocker arms? Also, would you need to change push rod lengths if you switched?

Trevor @ Texas Speed & Perf.

iTrader: (3)

Just divide your current overall lift by 1.7 and then multiply by 1.8. That will give you the new lift w/ the 1.8:1 rockers. For example: (.500"/1.7)x1.8 = .529" So, if you had .500" lift with 1.7:1 rockers, you'd end up with .529" lift with the 1.8's. Yes, you'd need longer pushrods, but kits like the one from Crane comes with everything you need. IMO, 1.8:1 rockers are a waste of money. You'll see VERY little increase in power, if any at all, from the added lift. We also have factory roller rockers.

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 Trevor D:
<strong>Did you say 2.18"/1.625" valves? Are we talking BBC heads for the intake? <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">C5R heads <img border="0" alt="[Fluffy]" title="" src="graemlins/fluffy.gif" />

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 Trevor D:
<strong> IMO, 1.8:1 rockers are a waste of money. You'll see VERY little increase in power, if any at all, from the added lift. We also have factory roller rockers.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Would an increase in lift of 0.035" be any use with a set of heads that have 2.180"/1.625" valves? I need to buy a set of rockers for the heads and the price difference between 1.8 and 1.7 is basically nothing. Also, aren't the 1.8:1 rocker arms suppose to give a quicker ramp up speed?

<small>[ July 23, 2002, 12:53 PM: Message edited by: ls1290 ]</small>

Trevor @ Texas Speed & Perf.

iTrader: (3)

Did you say 2.18"/1.625" valves? Are we talking BBC heads for the intake? <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />

VAP

The increase from 1.7 to 1.8 rocker gives an increase of about 8hp above 4500 rpm with a std factory ls1 camshaft & springs ,but also makes the motor valve float around 5700 rpm ( earlier than factory std ) Due to the added weight of the screw in stud type rocker.....(eg Crane )
A shaft mounted 1.8 rocker ratio might be different ....

The standard factory rocker ratio of 1.7 is high enough and unless you will be getting a cam with ramp rates to suit this rocker ratio i don't think your springs will last, as valve train stability might not be there...

<img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

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 VAP:
<strong>(1) A shaft mounted 1.8 rocker ratio might be different ....

(2)i don't think your springs will last, as valve train stability might not be there...

</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">(1) I plan on using the Jesel C5R shaft mounted rocker arm assembly. I think now that I will most likely use the 1.7:1 ratio version.

(2) I will be using Comp Cams 1.550" Hi-Tech Double Valve Springs which are good for lift up to 0.680" and 210# closed.