[ltlgto]

I am installing a set of Harland-Sharp roller rockers in my 455. Will I need tall rocker covers, or will the stock ones fit? If not, would double-gasketing work? Thanks

[ltlgto]

I am installing a set of Harland-Sharp roller rockers in my 455. Will I need tall rocker covers, or will the stock ones fit? If not, would double-gasketing work? Thanks

[Dick Duclow]

Stock covers will fit

[ltlgto]

Thanks for the quick response.

[Rocky Rotella]

What ratio rockers are you going? If you're going higher than a true 1.6 ratio, have you clearanced the pushrod holes in the heads? You may encounter pushrod bind from the increased ratio because the pushrod is closer to the fulcrum to achieve the additional ratio.

Just something to consider.

[David Jones]

I've read lotsa stuff on the various forums that has to do with clearancing the pushrod holes when you use 1.6 or 1.65 roller rockers. Some say you must, some say you might, some say you don't have to. Is there a solid answer? Are some heads open enough? David

http://kurtspontiac.homestead.com/DavidJones69GTO.html

[Blackcat]

Tosses a hand full of bent pushrods at Dave! [img]/infopop/emoticons/icon_eek.gif[/img]
Best to clearence the pushrod holes! it's a crap shoot and the cam lift and duration also play into the formula! [img]/infopop/emoticons/icon_rolleyes.gif[/img]
Tosses a bunch of busted springs after the Pushrods! [img]/infopop/emoticons/icon_eek.gif[/img]
Um, You had better also have the clearence for the 1:65's in the coil Dept! Coil bind does wonders for your Engine! [img]/infopop/emoticons/icon_rolleyes.gif[/img]
Been there Done that! [img]/infopop/emoticons/icon_wink.gif[/img]

Usually I'm found working on my Pontiac. If you want to find me Look for the white picket fence and all the old Pontiacs parked outside. And the half dissembled engine sprawled all over the driveway!

[455Dave]

Be careful with the HS rockers. My 1.5s are more like 1.6 ratio. I've heard the 1.65s run closer to 1.7 ratio. If you are running close to you max allowable lift based on a 1.5 ratio (like I am), the HS rockers can be a surprise.

Blackcat:

You forgot to throw a bunch of beat up cam bearings after the springs. [img]/infopop/emoticons/icon_wink.gif[/img]

[ltlgto]

I am running the 1.5's. The HS 1.5's run out at closer to 1.6? I haven't heard that before. I will carefully check before running this motor. Thanks.

[Rocky Rotella]

Can't comment about the ratio but I think you'll be ok. We run a true 1.6 ratio without modified guide holes without any bind.

[GoatRider]

I have also heard that the HS 1.65 is actually closer to 1.7 That could be a GOOD thing if planned for accordingly.

But are they a consistent 1.7... Or do the people who have been saying this mean the actuals are all over the place from 1.6 to 1.7 amongst a set of 16 rockers?

"Nothing Beats an Ol' Goat..."

[455Dave]

With a .360 lobe lift, we got .567 gross lift measured at the retainer instead of the expected .540 lift.

With a .3706 lobe lift, we got a .588 gross lift instead of a .556 lift.

This should help out a bit with the new heads but I was scratching MY head a bit till I remembered some old emails on the subject.

The measurements were made with a mag base mount dial indicator positioned on a plate that bolted to the valve cover bolt holes and a set of checking springs. The dial indicator was solidly mounted and checked for alignment with the valve stem.

[74GOATBOY]

I've seen stock Pontiac covers with and without baffles in them. The baffled ones have four weld indentations on the top of each cover. I had to use a Dremel tool to cut them out before my HS 1.5's would clear. I think doubling gaskets would be prone to leaking, heck I always seem to have a small leak with just one. I have heard someone makes double thick gaskets but I suppose you could try Permatex between two sets too.

[thirdgen455]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by GoatRider:
I have also heard that the HS 1.65 is actually closer to 1.7 That could be a GOOD thing if planned for accordingly.

But are they a consistent 1.7... Or do the people who have been saying this mean the actuals are all over the place from 1.6 to 1.7 amongst a set of 16 rockers?

"Nothing Beats an Ol' Goat..."
http://www.wacomquartz.com/images/li...on2orqcopy.jpg
<HR></BLOCKQUOTE>

i wish i still had the e-mail but i don't. i e-mailed harland sharp about the 1.65's coming closer to 1.72, the responce from them was yes the do come out to a 1.72:1 ratio then something about being desined for a solid lift cam, and some other crap i didn't see why it would affect to way a rocker arm was made. but if you have questions e-mail them and ask, the tech guy responded very quick last time, see if they have a better responce this time

[455Dave]

Thirdgen:

That almost makes sense. With the 1.5 HS rockers, my cam comes pretty close to a 1.5 ratio "after" subtracting the valve lash. I wish they would advertise that true ratio of the rockers though.