• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

SLP Rocker Arms Do Work!

kwinsor

kwinsor

SM 2006
SM 2005
SM 2004
SM 2003
Full Member
Joined
Dec 12, 2002
Messages
922
Location
Greene, Maine
I installed SLP's 1.85:1 rocker arms on my supercharged 5.3L. Next to the supercharger this modification has made the biggest impact on performance.

The most noticeable improvement is throttle response. The rpms spool up quickly. I gave it a half throttle kick into passing gear from 50MPH, it felt like the tires were ready to break loose.

I was expecting an improvement when boost was applied but was surprised to see improved performance at the low end as well.With a vac/boost gauge, I can see when the S/C starts to kick in. A lot of everyday driving happens without boost from the supercharger so I get to see how the engine is performing as it would if it didn't have the S/C.

A lot of the perfomance minded Av owners probably have a cold air intake, some kind of performance tuned computer, a cat back exhaust and maybe headers. That is the basic setup I'm running until the S/C kicks in. The SLP rocker arms have made a big difference on the performance of the basic setup. I think the SLPs would make a big difference on a non S/C engine as well. You'll notice the difference when you carry a high gear into a hill. Instead of bogging into a downshift the rpms pick up and kick into a downshift.

The exhaust tone has changed quite a lot, even at the low end. It's gone from ruuumble to raaaapp. I guess it reflects the free revving change.

I wouldn't try these if you haven't uncorked the intake and exhaust. If you've got a cold air intake, headers and catback, and a performance tuned computer the SLP rockers will wake up the beast. Installation is pretty easy if you don't have a supercharger to get out of the way first.

kw
 
Cool... Which kit did you go with?

Any of them are a pretty penny, but I may have to look into 'em. :)
 
I got the mid priced kit, Didn't go for the titanium retainers and SLP springs.

kw
 
How hard was the install?

This was on of the upgrades I planned in the distant future, but looking at the valve covers and all the junk around them, I got a little discouraged.

Not to mention, I'm deathly afraid of dropping a valve into a cylinder. :)
 
The install is a piece of cake. The coil packs come off in one piece with only one electrical connector to undo. You've got a PCV line on each valve conver and that's about it. A lot of stuff passes by the valve covers but most of it pushes to the side.

I bought the tool kit they sell. It's a valve spring compressor and a fitting that looks like a spark plug for filling the cylinder full of compressed air while you change the valve springs. If you do one cylinder at a time you won't lose any valves.

The most technical thing was finding top dead center on #1 cylinder. I just turned the engine over with a socket on the crank pully. I watched as the exhaust valve closed and then felt through the plug hole for the piston to come to the top.

When all the rockers are installed you torque the bolts on half the rockers as listed in the directions, turn the engine 360deg and torque the other half. That's it for adjustments.

kw
 
Redaval, will you be taking the Av to the track for some 1/4 mile times this Spring?
 
I'm tempted to make a pass through the traps. Our local track is only 1/8 mile!

I've got a Gtech competition pro on the way. I'll have some legitimate 0-60 times later this week.

kw
 
I'm not sure about the GTG, but I know they used to have "Street night" as Wednesday night, and Friday night at as a more race oriented test and tune.

It's a ton of fun going up there any ol' time during the week to see what's running.
 
KW
GTG at Super Chevy Show / New England Dragway on the 24th of May
Be nice to see an AV run down the strip
Rich
Click to expand...

I might see if I can make it that day. Saturdays are usually busy for racing but the track hooks good.

Tom
 
Any info on how the rocker change impacts emissions? Unfortunately I live in a state that is moving from hose up the exhaust to tread mill emissions testing. It will be much more difficult to have internal mods go undetected. I have been "told" that computer program changes will now also be detected and cause a failure. What about mileage, any change there?
 
Any info on how the rocker change impacts emissions? Unfortunately I live in a state that is moving from hose up the exhaust to tread mill emissions testing. It will be much more difficult to have internal mods go undetected. I have been "told" that computer program changes will now also be detected and cause a failure. What about mileage, any change there?
Click to expand...

Hi Auto,

I can't see how this mod would change emissions. It's just allowing more of the air/fuel mixture that the computer made into the cylinder.

Mileage is the same or slightly better. No big change.

kw
 
Thanks. Do they fit under the stock valve cover? I was orginally looking at the Comp Cams GM Gen III rockers. They only have a 1.6 ratio. But will fit under the stock covers and won't move me to far from factory specs. Any concerns with the high ratio?
 
Do they fit under the stock valve cover?
Click to expand...

The SLP rockers do fit under the stock cover without any problem. It's a very easy install.

I'm running stock. Do you think if I replaced my rocker arms I would notice a difference?
Click to expand...

That's real hard to say for certain. SLP now advertises +18hp. The valves open more quickly and open wider so at some point in the power band the engine will be taking bigger gulps of air/fuel.

I think it's a logical 3rd step. Intake, exhaust and then rocker arms. Wouldn't makes sense in reverse order.

kw
 
Redshift said:
The SLP rockers do fit under the stock cover without any problem. It's a very easy install.


That's real hard to say for certain. SLP now advertises +18hp. The valves open more quickly and open wider so at some point in the power band the engine will be taking bigger gulps of air/fuel.

I think it's a logical 3rd step. Intake, exhaust and then rocker arms. Wouldn't makes sense in reverse order.

kw
Click to expand...


Thanks Redshift.
 
Hey guys,

Newbie to the board here. I'm interested in the rocker arms for my soon to arrive 2500. I checked on the GMgoodwrench.com website and found this for all big-blocks.

12368082_large.jpg


12368082 Long Slot Rocker Arm
These 1.7 ratio hardened steel arms have elongated slots to provide extra clearance for high-lift (.600") camshafts. This rocker assembly includes arms P/N 3959182 plus the ball and nut, for use on all 396-502 big-block heads with adjustable rockers.

Technical Notes: These long slot rocker arms are stamped "H".


hmmmm, I'm going to ask my GM perf. parts dealer about this one and try it out.

I'm trying to do as much research on GM Performance parts mods so I can roll everything into my 0.0% financing. :)

Thanks for all the info I've researched here on this great site.

I'm a long-time Chevy/GM man, it runs in the family.
 
one thing I forgot to check on the post above of mine, what rocker ratio do the 8.1L's come with?

here is a cam package for the big-block line up, I'll have to ask if it works with our 8.1L engines. It is from GM Performance parts, another mod I may be able to roll into financing prior to pick up. Hopefully it adds 75-90lbs of TQ and some minor HP. ?

From GM-
12361314 Camshaft & Lifter Kit - "Truck Torque Design"
This kit is for all big-block V8 engines. It is engineered to boost horsepower and torque from low rpm through the entire engine range. It enhances low-speed performance for all truck applications from normal driving to towing and hauling heavy loads. Suitable for computer controlled Mark IV and Mark V engines. Advertised duration (intake/exhaust) is 202?/210?, and maximum lift is .468/.485". Centerline is 110?.

I hope this cam kit applies to our 8.1L.

After these 2 mods if applicable, I think the "other guys headers" for the 8.1L or AZ Marine (when produced) would turn out some impressive gains as a combo. Adding in the cat-back exhaust would also be a nice upgrade.

I think I'm psyching myself up here. Anyone with me?
I could be out on left field with this one but I'm sure as hell going to try to work things out.


 
You are showing all the classic symptoms of the modification disease. Too much horsepower is just not enough! ARH! ARH! ARH!
 
You must log in or register to reply here.
Back
Top