gokussx4

iTrader: (3)

Just got a set of 241 cast heads ported by CFM. Intake at .600" lift I get a 305 airflow. The numbers start to drop after that. Exhaust is 208 at .600" and keeps climbing.
Aftermarket stainless steel valves have a 2.02" intake and 1.6" exhaust diameter.

I was thinking about the xr281hr grind from comp cams as this should put me around a .571" lift, with stock rockers.

My thought was get a 1.7 ratio rocker set to put me near .600" lift, thus getting the best airflow with my new heads.

Heard some old war stories back in the early 2000's with problems with some of the aftermarket rockers for the ls1 out there. What have you used and how has it treated you?

Not looking for someone to post on what they just bought, no offense but looking for real data. Thanks!

Z28/2002

iTrader: (27)

Stock ratio is 1.7

gokussx4

iTrader: (3)

sorry mistype there. thank you for the correction.

so 1.8 rocker suggestions?

LS1-450

iTrader: (33)

If you're buying a cam, why not just buy a cam that gets you close to .600" lift using stock 1.7's?

camaroz28lt1at

iTrader: (16)

If you have the money and going with a high lift cam I would stick with 1.7 ratio and get a set of yella terras. If Im not mistaking stock rockers like to side load the valves when you get agressive with the cam. Please correct me if Im worng.

garygnu

if you have the stock rockers just upgrade them with some compcam trunnion bearings.maybe consider a custom cam,or a LSr cam from comp.

gokussx4

iTrader: (3)

What about the benefits of having roller rockers?

LS1-450

iTrader: (33)

There is the benefit of being able to adjust a narrow valve wipe pattern w/ an adjustable roller tip rocker, which the stock rocker doesn't offer. Either way, the 1.7:1 ratio is the ratio to stick with.

gokussx4

iTrader: (3)

Thanks LS1-450. What roller rockers do you use and have you had any issues?

firehawk196

dont no how ur moneys are but i have nuttin but SLP on my firehawk yes very very pricey but to me its well worth it JMO

LS1-450

iTrader: (33)

I don't use them anymore. Now stock rockers are used. Have used 1.7 rollers w/ XER lobed cams & 1.8 rollers on stock lobed/low lift cams. IMO, roller rockers are not worth the expense.

One thing to watch for with stock rockers & higher lift aggressively ramped cams are the bearing retainers popping off & dumping needle bearings into the head/engine. There is a kit sold that is a cage for the needle bearings that eliminates this problem. To me, the kit is also over priced. So, I just tack weld the retainer to the rocker. This keeps 'em from popping off (see pic).

gokussx4

iTrader: (3)

Very interesting idea, so you didn't notice a noise difference with your roller rockers? Also, I have heard that having lighter rockers helps with the top end power at higher rpms because of less weight and friction. Thoughts?

LS1-450

iTrader: (33)

If the concern is weight reduction, then hollow stem valves can be used. Lightweight valves are a much better benefit than light rockers. The valvetrain harmonics will benefit from hollow (sodium filled) valves over rocker mods. As far as friction, yeah, it is less w/ rollers, but, again not worth the cost, IMO. Best improvement from using adjustable roller rockers is the ability to have a narrow centered valve wipe pattern. Noise...? The resistance of dual springs that are required for higher lift, more aggressively ramped cams, will make more noise regardless.