1.6 rockers

[DusterBoy15]

i was told by a member that i should get some 1.6 rockers to get a little bit more lift for my xe274 cam should i get them for a little more go?

 

[GoodysGotaCuda]

Doesn't always mean you get a little more go. Testing/Dynoing has been done before to show not every engine picks up from it. Depends on its volumetric efficiency, they change duration, you also need to make sure you have the piston to valve clearance before you start sticking it further in the cylinders.

 

[ramcharger]

Not to mention spring retainer to guide clearance and make sure you don't have spring bind. Don't overthink your build. Quality rollers are big bucks and the gain is very small if there is a gain at all.

 

[dust]

If you want to up your cam specs a little than 1.6 rocker arm ratio is the way to go. But the choices are limited when buying new arms, you also may want to look into 1.6 intake a 1.5 exhaust arm sets too.

 

[DusterBoy15]

thats what i thought. not worth it.. ok thanks guys

 

[cuda66273]

Going to a 1.6 rocker does not change the duration, the opening and closing points in drgees of cam/crank rotation are the same. What it does do is obviously open the valve deeped and because it has farther to travel in the same degrees of rotation it opens and closes quicker. This helps to trap more cylinder pressure=HP gain.

Running a 1.6/1.5 combo can help bring in the tork a littl;e sooner in the RPM range by increasing the avalability of fresh Fuel and Air during the overlap and by opening the exhaust the with the 1.5 it will increase scavenge allowing for a cleaner sweep of the combustion chamber....higher percentge of fresh A/F allowing the motor to burn more fuel = More Power.

Of course how much improvement depends on many things from compression to head flow but you will normally see about 25-40 HP on a well built bracket or hot street motor and it will improve low end tork by moving the tork band down anywhere from 100 to 500 RPM.

 

[lead69]

They will make the cam act about 3 degrees larger in duration-it wont actually spec out larger but it will act larger.The thing is if you have heads that stall at or around .500 lift you really dont need them,not to mention the gain you will get in an average street built enigne just doesnt add up to the money spent.If your looking at every tenth or have well ported heads I would reccomend a custom grind or look at the xe high lift series or lunati voodoo that has the lift built in,its alot less expensive.

 

[cuda66273]

Pass.....I'm not going to get into this discussion.

 

[lead69]

I would ask you to enlighten us Don,but I already know your answer-but feel free to pass on to others your thoughts!.

 

[DusterBoy15]

so later on they might be a good bolt on

 

['64 Cuda]

It DEFININITELY wasn't a Mopar, but I had a 63 VW with a 1200 cc 40 HP engine that had a set of big bore cylinders that took it up to 1385 cc, a mechanical advance distributor, & a header. It came stock with 1 to 1 rocker arms. Later models had 1.1 to 1 rockers. I bolted on a set of the 1.1 to 1 rocker arms (giving a theoretical 10% increase in lift) & you could feel the improvement in performance.

 

[rumblefish360]

so later on they might be a good bolt on

Correct. But the hardest thing to actually find out is if it is worth the expense and where to put the larger ratio. On the intake or the exhaust.

The larger ratio will make the cam, more intsense, not bigger in duration. More lift is directly related to HP. Duration is RPM.