The advice from the machinist was not to go crazy with expensive rocker arms for my 383 build. Easy to say, but are self aligning better? It's a street driver, no track time.
http://www.summitracing.com/parts/sum-g6910b
http://www.summitracing.com/parts/sum-g6935-16
Scorpion
http://www.skspeed.com/ProductDetail...ductID=SCP1000
Any of these from China?
It's a Comp retro cam, should I use Comp rockers?

 

Your rockers don't need to be from the same company as the cam- There is nothing that makes them a 'matched set'.

I personally run the Scorpion Endurance series (fit under my stock valve covers) and like them.
The price is right and they are US made.

 

Thanks for info, I forgot to ask if they fit under the stock height valve covers. The heads are Brodix IK180 and I just don't want any problems with the geometry, that's why I asked about the brand.

 

Are you sold on aluminum? My engine guy actually strays away from them for street use because of the amount of dimensional change they undergo when heated, especially if you're running a solid setup. Durability would go to Chromoly or Stainless Steel. They aren't quite as sexy looking, but would serve your purpose just as well.

I'd definitely go the needle-bearing route instead of the ball joint route.

I forgot what brand my guy like to install, but he has a set of AWESOME Comp Cams Stainless Steel that are too expensive for me.

As far as height, I think you're OK with most choices until you start getting into running a stud girtle.

If you have screw-in studs for your head, I'd consider upgrading to a 7/16" system over the standard 3/8" system. Just more metal there and a minimal cost to upgrade. If you're running any type of lift on your cam (requiring higher spring pressures), your engine will thank you.

And if you're running solid lifters, definitely consider polylock nuts. They hold adjustment much better.

 

this is what I run.... a little pricey... $340.... but great RR..

http://www.summitracing.com/parts/cca-1617-16

 

I'd like to see some technical info to back up that claim.
I'd buy that steel or stainless is stronger but dimensional change? The amount of change on such a piece would be insignificant at best.
If this was such an issue CF would be rife with threads on it since 80% of the population running roller rockers are running aluminum.
You get more dimensional change from running aluminum heads.

With that said, I run aluminum 1.6 Scorpions on my Aluminum heads with a solid, flat tappet cam and my valve train has zero issues.

I would avoid the 'self-aligning' nonsense if you're moving to roller-rockers and stick with guide plates.

 

If you want a trouble free operation, dont use that roller stuff for a cruising engine...there is some merit for racing but not for the street at any price...even if they were free.....stock long slot rockers is a wiser choice

 

I talked to CompCams extensively before buying the Pro magnum 1.52 SS RR.... and they also said the Aluminum do have some flex, thus why they are always so BIG, and they ware out much faster... they also claimed that the SS RR that i run are built in such a way with the fulcrum/pivot, that the have less mass to move... thus higher RPM with out float.


not true..... MOST all modern engines run full roller valve train.... why? longevity mostly.... the first thing to ware out on an old motor was the cam usually... also better MPG from less resistance in the train... which equals more HP//....

 

Since your machinist is saying that, I'd guess it's a fairly mild combination? Planned HP goal? Max RPM? Which cam?
In a street engine with mild to mid level cam, just about any rocker will work, but go full roller, it's worth it. I mean, what's the point of building a new motor for more power only to knowingly limit it?

Either way, if your heads don't already have guideplates installed, get a set and avoid the self-aligning. Due to the size of most of the aluminum ones, they don't usually fit under stock valve covers easily (some do, some don't), but the steel ones usually do. For the record and reference, the Crane Energizer alum don't fit under stock covers.

 

My apologies. I wasn't very clear. There is static dimensional change due to change in length, and dynamic dimensional change due to flexing when hot.

Unless you're spinning 10k+ RPM, there is no benefit to decreasing the reciprocating mass in the valvetrain. A solid set of needle rockers such as Mr. Pauldana identified, are wicked awesome and VERY stable for a street car.

As far as Mr. Ironcross' mention of NOT installing roller valvetrain...well that just doesn't make any sense. You are relieving the valvetrain of a TREMENDOUS amount of friction with a full roller configuration. No more worries of a wiped cam. And depending on who you listen to, you are talking about a conservative 20 HP gain (almost certainly more) by going with a roller setup. Not to mention the more radical profiles you can run with roller lifters.

I'm not knocking those that keep "regular" parts in their car. In the end, they ARE probably more reliable. I honestly have no doubt about that. But the reliability comes with the lack of stress you're putting on the parts because of the extremely mild setup. Mild setup means less RPMs. Less RPMs is less stress. Less stress = longevity. Period.

Lets say you have a "new stock" setup. No improvements. You push out 270 hp for 300,000 miles. Great. Wonderful.

Now build a "roller" setup with hot cam, full roller, hydraulic lifters, new heads, 10:1 compression, and all the fun little bits that go along with it. You push 500+ HP out of the engine, but need to rebuild it after 100,000 miles.

I would be amazed if I put 2,000 miles a year on my car. That would equate to 50 years on the engine in question. I promise, something else is dying (probably even me) before I need to crack into that engine again. And I've enjoyed DOUBLE the horsepower the whole time.

Just my thoughts.

 

The big differences are the stock rocker ratios are all over the map. 1.38 to 1.50 ratio, many times in the same engine. I have broken 4 factory rocker arms in my lifetime as well so I can't confirm they are all that durable. I have the same rockers as Pauldana in my 383. On a stock, low performance engine this ratio variation is minor but with better heads, cam and higher performance the difference is more pronounced. Also reduced friction is always good. If you want to stick with a factory style rocker you need a long slot style if your cam lift is higher. These are a good option.
http://www.summitracing.com/parts/lu...make/chevrolet
If you want a full roller I have used these with good results at a reasonable price.
http://www.summitracing.com/parts/cc...make/chevrolet

 

I went with Harland Sharp. "100% American Made Parts manufactured out of 100% American Made Materials"

They have been making roller rockers since the 60's right here in the USA. I would give them a call and talk to them about your exact set up and get their recommendation.

http://www.harlandsharp.com/contact.htm

 

Definitely going full roller, this is not a daily driver and high mileage wear is not an issue.
ezobens - the Scorpion Endurance is in my budget.

keithinspace - thanks for the concern about dimensional change, I am at about 400-425hp, hydraulic not solid. I think the aluminum will be able to dissipate heat fast enough to avoid serious distortion.

Ironcross - I think the full roller will be more efficient than stock with the retro roller cam.

pauldana - I checked those rollers out, pretty nice. I may justify buying them using the aluminum distortion (myth?) Do they fit under the stock height covers?

63mako - I did see those on Summit's web site. I also saw that you use the same ones as pauldana!

johnt365 - which ones did you go with?

 

I went with these http://www.summitracing.com/parts/cs...make/chevrolet my heads have guide plates and 3/8 studs I used the 1.5 ratio. I also have aftermarket valve covers so can not verify if they will fit under stock valve cover.

I did notice that Scorpion is made in USA also which is a good thing to me.

 

What is the spring pressure @ max lift? If less than 375# The Scorpions would be great. Aluminum rockers do a great job of absorbing shock and harmonics in the valve train.

 

63mako uses them because they are some of the best.... yes, they fit under stock valve covers, BUT, i still purchased a 1/4" aluminum valve cover spacer off ebay...why? they are close... and also the oil windage went way down with the extension/lift of the VC,


also... keep in mind, most SBC heads will NOT accept a 1.6RR, the pushrod holes need to be elongated for the 1.6 or they will rub... the 1.52 fit fine.

 

The 1.5 ratio was the original plan, I am well into my target compression/HP without moving to the 1.6. Also, the machine shop bill is high enough now without reworking the heads!
Just to make sure of the rockers you went with -
http://www.summitracing.com/parts/cc...make/chevrolet
It's either these or the Scorpion Endurance
http://www.summitracing.com/parts/sc...make/chevrolet
Thanks!

 

I run Scorpion Roller Rockers with a .578 lift Howards Racing cam .. street driven regularly, never had any issues in 4 years

 

Would that be the Scorpion Endurance Series and if not, did they fit under the stock height cover?

 

http://www.summitracing.com/parts/cc...-size/5-7l-350