what is the advantage to 1.6 rocker arms over stock 1.5's

would i benifit any from putting these on my stock 305? or a built 305 with heads/cam?

 

1.6 rockers raise the lift and the duration without REALLY raising the duration. Installing the 1.6 ratio lets the valve lift higher, which keeps the valve open longer, which is increasing the duration theoretically. TECHNICALLY, its not however, because the duration is ground into the camshafts lobe profile. So in short, installing 1.6 rockers gives the EFFECT of raising the duration 1 or 2° at most without physically changing the lobe profiel. And it also increases the overall valve lift.

To get the lift with 1.6 rockers, divide the lift by 1.5 and then multiply by 1.6. Or, just multiply the lobe lift by 1.6.

Do a search, this has been talked about before in detail. I pretty much summed it up.

Advantages: the cheaper way to increase duration SLIGHTLY as well as increasing the lift a bit. Its either this or a cam change.

 

so i can just shove these into my 305? it is a noticable gain?

 

Well, what is your valvetrain setup at the moment?

 

stock, except for my 3.73's which come real soon

 

Anyone who installs a gearset into their valve train is a TRUE hot rod artist, in my books

Anyway, if this would be in conjunction with whatever cam you decide on from your other thread (these could have all been in the same thread, but oh well), then i think that 1.6 rockers would be a fairly decent addition. they can be had on ebay for fairly cheap, yes even new ones. Then comes the question...do you risk aluminum rockers?

 

i kept all my threads seperate to avoid cluster, and help future searches that remain on one topic, but now thats out of the way,

whats wrong with aluminum rockers? advantage and disadvantage?

 

Aluminum rockers fatique quickly and can break from stress. i have heard stories of them breaking at like 30,000 miles. I do not know how common this is, though. If you can spare the change, Comp Pro Mags are made of steel. They are lighter and stronger than aluminum. And i think they have a lifetime warranty so Comp will replace/rebuild them.

 

sounds like a waste of money, i'd stick with basic 1.6's

 

Most 1.6's you will find are some sort of aluminum i think.

Comp offers Magnum roller TIP rockers, those are steel. But they are not full roller design.

 

comp 1318s are steel and fuller roller trunions. biggest advantage in going with aftermarket part is the gm pieces aren't really 1.5 and prone to flexing.