I was wondering if anyone has used SLP 1.85 rockers with the GM ASA cam?
I was looking at roller rockers but keep finding issues (weight over valve, valve float ect). I was wondering if the slp stock style would be better?

I found a set for $200, 600 wouldn't be worth it in my opinion.

Also I checked PTV .083 exhaust .121 intake when I put it together, does anyone know how much they would change duration?



I have a LS1, PRC Stage 1 heads milled .30, .045 cometic head gaskets, with Howards version of the GM ASA cam. (226 236 .525 on 110 LSA), LS6 intake, 1 3/4 bbk lonetubes, no cats, open borla, 85mm throttle body 85mm maf slp lid, 160 thermostat, underdrive pulley, 42lb injectors, and tune.

 

The higher ratio doesn't add duration as that is a constant which is ground
into the cam profile. They will somewhat trick the engine into thinking it has
a few degrees as the valve will be moving faster/sooner and ultimately about
.045" more total. Some cams are just ground too aggressively to use those
rockers however that Howard's version should be alright. I would definitely
make sure that your valvesprings are in great shape, and should be duals.

 

Thanks, I did put PAC1218 springs when I installed the heads.

I contacted Howards and they said the rockers would be fine.

I was just kind of curious if anyone has tried this?

I'm not disappointed in the way my setup turned out, just looking to optimizes what I have now. I put down 427rwhp 390 ftlbs

 

Even though the lift is low(.525") the lobes on you Howards cam are somewhat aggressive. I'd use some PAC 1211x springs for better control.

 

The higher ratio does affect duration at the valve slightly. But you have enough clearance that there won't be an issue.

I don't know about those SLP rockers, though. They have an upgraded trunion vs stock, so they might be okay.

And as long as you have about 145lbs of closed spring pressure and around 370-400 open, you'll be fine with that cam and rocker combo.

 

With the PAC1218 the closed is 130lbs (1.8") which isn't to low, but the open is just 318lbs (1.2").
IMO too low!
PAC1211X is 130lbs(1.8") and 370lbs(1.775") which is what I'd go with in a beehive (single) springs.

 

Honestly, I would just save your money and a potential headache. Put the money towards a fast intake or something else.

 

Yeah, I would like the fast setup, but 1200 for 10 hp is kind of hard to eat.

I know I know, you gotta pay if you want to play. Lol

 

IMO, if you plan to stick with your PAC1218 springs then I'd get back on the dyno ASAP, after the rocker install so you can see your gains and if you're getting any valve float in the upper rpm range, which you should be able to see in dyno graph. If any possible sign of V.F. is seen then get some stiffer springs in there ASAP, otherwise enjoy!

 

Thanks for the input guys. Didn't really think about the springs being an issue. Guess it time for new ones.

 

Do you know the installed height of the PAC springs you currently have? If not, get a valve spring micrometer and measure. Then figure out your distance from coil bind and buy some shims. The shims will increase both seat and open spring force.

 

Get off the wallet and do it mike

 

PAC1211X single beehive springs would be a good choice, and they're only $150 at the ws6store.

 

Thanks already on order. Sometimes I wish I never found that place. lol

 

They also have the fast 92mm for $815, Hinson had them for 749 shipped for Black Friday. I'm king of kicking myself for not jumping on it then.

 

Sorry to bring this thread back from the dead but I'm thinking about a ASA cam and had a few questions.
With the 1.85 rockers and .525" lift how much extra lift does that translate to ?
With the .045 gasket and .30 mill what length and brand pushrods ?
Has it been tuned yet; what did you put down ?

 

.525/1.7 = .3088 of actual lobe llift. Multiply by 1.85 = 0.571 of valve lift

 

Actually, it does.

There are two duration's listed on nearly every cam card, and the durations are based on lift points.

The first is the advertised duration, and that's at the first measurable point off of base line, usually 0.006", or somewhere around there. Changing rocker arm ratio's will not alter this.

But, it's generally accepted that airflow doesn't really start until the valve hits 0.050" of lift. That's where you see the second set of duration numbers. This is the point that's accepted to be where the cam starts working. A higher rocker ratio not only increases the total valve opening, but also how quickly the valve gets to that effective point.

Increasing the ratio increases the effective duration by about 2-3* or so at each end. Many dyno tests have proven it to gain a little bit of power here and there; depending on the rest of the engine, of course.

 

Wow thanx SSCamaro99_3 and .boB. This cam makes sense to me. For three months of the year I could drive a 229/239 0.571 cam by only wrenching under valve covers and flashing a new tune. End of summer, throw in the stock rockers and be down 20hp but get extended spring life. It would need seperate tunes right ?
It seems like a designed exhaust could really help this cam. Could someone suggest one ?

 

I doubt it. We're only talking a few extra degrees of duration and a little bit of lift. It's not like a whole new cam. If you're very astute, you will notice a small improvement. When I did this to my truck, I noticed some improvement while towing, otherwise it felt the same.

Same thing with the springs. No need to keep changing back and forth. You'll probably create more wear and tear by changing things twice a year. Put them in and leave them there.