[Peti972]

Are Harland Sharp 1.65 ratio roller rockers top of the line? Also was wondering what does a stud girdle do and where is it installed? Lastly what would be a good combination for these roller rockers? engine is solely for cruising btw no drag racing of any kind strictly street 400 cu in

[gtofreek]

Originally Posted by Peti972

Are Harland Sharp 1.65 ratio roller rockers top of the line? Also was wondering what does a stud girdle do and where is it installed? Lastly what would be a good combination for these roller rockers? engine is solely for cruising btw no drag racing of any kind

They are a decent street roller rocker. I wouldn't call them top of the line by any means but for what you are looking to do, they would be fine. I have used them on many engines with no issues.

The stud girdle mounts to extra long poly-locks, above the rockers. This keeps the rocker studs much more stable so they don't flex around so much. If you run stock, iron heads, and you have a cam that will have more than .500" lift with those rockers, then you may need to grind your pushrod holes in towards the rocker studs so the pushrod doesn't rub on the head. It gets real close with 1.65 rockers so it will need to be checked.

[chiphead]

HS rockers are good units for the money. Like GTO said, you must clearance the head's pushrod guide holes to prevent crashing the pushrods into the heads. Any high lift rocker arm with 1.6 or more ratio is going to move the pushrod closer to the head, which often causes damaging contact between pushrod and head.

Stud girdles are to prevent the studs from flexing in extreme HP drag motor applications. Totally unneeded for you, unless you plan on running a cam with more than .600" lift and 400lbs+ spring pressures at 6000+ RPM. Total drag race stuff.

It would be best to lay out the total combination of parts for us to help you. It's easy to screw up a pontiac valvetrain if you don't have a strong grip on the essentials.

[mkpontiac]

Paul

Are you saying that in most cases as long as your total lift is not greater then 0.500" you do not need to elongate your pushrod holes?

Mark

[gtofreek]

I am saying it should always be checked. I ran an Erson Hi-flo 3 cam years ago with 1.65 Erson rollers without elongating the pushrod holes and had no problem with contact. It had about .525 lift. There can be slight differences in heads also. The more lift you run, the closer the pushrod gets. Usually, in the cases I have seen, when you are running low lifts[under .500] it hasn't been a problem. I'm not going to say that's in all cases. There are just too many variables that can change these things. How much was decked off the block and heads, pushrod length, rocker arms themselves, cam base circle, all have an effect on this, so best bet is to never assume and always double check.

[HWYSTR455]

If the heads are off, do the holes, no reason not to, regardless of what lift you're at now.

If you have a choice, run 1.50 rockers, and order the cam to what specs you want.

Top of the line rockers I would probably say are the Crowers, though the PPR ones are a close second. And those are I believe less than the HSs.

Buy good ones and don't look back. You can use them for the next several builds without worry. More accurate ratios and smoother operation are just a couple benefits.


.

[Mr. P-Body]

While I agree HS rockers are "good for the money" and I also agree Crower are among the best, Chinese knock-offs are okay, but hardly "top shelf". It's okay, we sell them too, just be aware of what's "out there".

Comp also makes first-class rockers in both aluminum and steel. Unfortunately, the "Pro Magnum" and "Hi Tech" rockers aren't available in a "true" Pontiac design. The small block Ford stuff fits fine, though we HAVE heard of issues from others.

Scorpion is probably the "best for the money" today. Made in USA, they are VERY strong, and have much lower rate of "deflection" than the HS.

I also agree, no need for 1.65s in a street-driven cruiser. And it isn't the max lift that presents the problem with 1.65s. The socket for the pushrod is necessarily moved much closer to the stud to achieve the increase in ratio, making the pushrod also much closer to the stud. The distance between the stud and the valve tip will remain "constant".

I've seen the results Paul speaks of without modifying the heads, but that's the exception, not the "rule". Modify the pushrod holes if you're going to use 1.6 or higher ratio rockers. Cheap, easy and "no worries" later...

Stud girdles are, for the most part, for use in high revving race engines. "High revving" means 7,000-plus. Some of our customers have reported some high-end power gains when running high spring pressure on fairly large rollers, in the 6,500 range. For your application? MASSIVE overkill.

Jim

[Peti972]

hmmmm I will prob have more questions later but for now I'm trying to save up $$$ for a carb & intake thanks for the help & advice guys I really appreciate your feedback

[Half-Inch Stud]

I owned HS 1.65s and they were sloppy-loose in the hand, yet work very well (precisely) in the motor. They re-sold at a high price for advertising them as sloppy-used but good.
I would re-own these sloppy roller rockers if given the choice.

I owned Crane 1.65:1: they hit the Spring retainer. they hit the M/T valvecovers with 1/4" valvecover gaskets. Hit at the Bolt castings.
They were not sloppy.

I OWN Crane 1.5:1s and they seem fine. I use the 1/4" Valvecover gaskets.

I OWN some el cheapo 1.65:1 Roller Rockers (cast aluminum), they appear weaker than the Crane, but after 10,000 miles and some 1/4mile activity they did fine on the Intake side. Wonder how they would do on the EXH side.
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I would use a strong rocker on the Exhaust to open that high-PSI valve.