Hi,
I have read that the stock rockers are weak and flex, and the bearings in them tend to come apart.
Then I read a post here the last couple of days and guys saying that the stock are as good as aftermarket, and " shouldn't fix what isn't broke".
I am totally confused as I just ordered a set of 1.7 from Harland Sharp.
I called Harland before ordering and was told that the old rockers would flex, so not a true 1.7, and their rockers would bolt in, NO mods to valve covers.
I was also told that a stock LS1, with no other mods except the 1.7s added 10-14 HP on the dyno.
Now, I do realize they are trying to sell me something, so HP gains aside, the main reason I ordered these was to have less friction, and reduce the chance that I have a needle bearing floating around where it's not needed.

I would love to hear from anyone who can educate me.

Thanks,
Jw

 

In my opinion, a lot of aftermarket rockers get a bad rap. I have looked at the wipe pattern across the valve stem and to be honest, that would be enough for me to change to a full roller setup. I have been running the Cranes for a couple of years, they are high quality rockers and are very quiet.

The stock rockers were designed for stock springs. They do flex but not to a point you will notice. For that matter, all rockers flext. The thing you have to watch, is not weight but rotary mass moment of inertia, with regards specifically to the rocker that determines the forces required to accelerate the valve train. Higher values require more spring forces (stiffer springs).

There are a lot of guys running the Harland Sharp rockers, and love them. Just make sure your springs are up to the task of the job and you will be fine. Your valve guides will like the roller tip much better than stock, because the wipe pattern will be improved. If you look at the wear pattern on the stock rockers, you will likely find some that don't even apply the force in the center of the rocker, but off to the side. Based on your main reasons for buying, less friction and better bearings, you will get both. Your valve guides will also benefit.

The stock rockers also come off the seat at a 1.54 rocker ratio, not 1.7. They only achieve the 1.7 ratio when fully open. There are different arches that a rocker can be designed to swing through, over-arching, under-arching, etc. Not sure on the Harland Sharps how they are designed, but my guess would be they would provide a more true 1.7 arch and therefore your valve can be at a specific opening height for a little longer duration.

 

Any way you look at it, the stcks are just fine for higher hp applications. Hit the search button. Look at how many people have aftermarket rocker failure. Especially with Harland Sharp. (They tend to break at the tip)
The stocks are more than fine for 95% of all applications, but EVERYONE will have a different opinion.

Am I running the stocks?? YES. AND I am well over 800/800 to the rear wheels. I have ZERO rocker issues. I chose the stocks for a few reasons. 1)Weight... Believe it or not they are a nice and light rocker. 2) They've been proven in dozens upon dozens of high hp applications.

Their kinda like the stock lifters. Everyone will replace them, but when you talk to the "Real" tuners (Like ECS) they will tell you to stay with stocks.

I guess what I am saying is, is your money is better spent elsewhere.
Just go with whats been proven time and time again, and with what works.

.02 has been deposited.

 

Thanks to both of you, vettenuts and american_hp for your comments, as this is the very disparity that I am confused about.

As an " average" mechanic, I have to trust the opinions of others and decide for my self. At this point, as I have already ordered the Harlands, I will install them, I just hope they will clear the covers,as I am not sure if that is something I can fix.
I have changed the cam, with help from someone who knows alot more than I, and swaped out the pushrods for a stonger manly rods.

Thanks again for your respones, and would love to hear from anyone else as well.
Jw

 

 

If ECS and AmericanHP say keep the stock ones, then keep the stock ones. I think AmericanHP has tried just about every Corvette part in existence! Sorry Jeff


Clayton from Las Vegas

 

The only aftermarket issues I have seen are the Harland issue you mentioned (which I thought was straightened out a year or two ago) and the heavy Yella Terra float issue, which I thought was resolved with their newest re-design. Are there others? Just curiosity on my part.

 

Thanks again for all the responses, I am vacation the rest of this week, but will post an update on the install next week.

Would love to hear from someone who has actually done an install.

Later,
Jw

 

If you mean an install of the Harlands, none other than EG had them on his car.