I put a Howard's boost cam in my lq4 its a 224/234 115 Lsa and 612/638 lift and I'm having a bit of trouble with it breaking my rocker arms and I believe that it could be my pushrod length since it's a stock length 7.4 but I'm not very experienced in this so I'm hoping that someone could help me out here or tell me what else could be causing this

 

Pushrods would have to be way too long to be the root cause.

What springs are you running?
Did installer degree the cam when you installed it to verify centerline?
Did installer verify PTV clearance?

 

Pushrod length must be verified when changes are made that deviate from stock such as camshaft, heads, valves, rocker arms, lifters. You'll need to invest in a adjustable PR length checking tool and the COMP 7702 is what you'll need to determine PR length. Make sure your on the base circle of the cam before measuring PR length and to do this you'll want to use the EOIC method.

Exhaust opening and Intake closing is what this means. Let's say your working on cylinder No. 1 and you want to determine the PR length for the intake rocker. What you'll do is turn the motor over by hand or get yourself a remote start switch so you can bump the engine over to watch the valve events. When you see the exhaust rocker arm begin to open the exhaust valve for No. 1 you'll then know the intake for No.1 is on the base circle of the cam. Now with your PR tool you can measure for proper PR length. To do the exhaust you will bump the motor over until you see the No. 1 intake rocker arm fully open the valve and then begin to close and then you will stop. Now the exhaust for No.1 is on its base circle of the cam and you can now measure for it's PR length.

 

Check your valve spring setup. maybe coil bind. If there isn't enough clearance between the coils of the spring when the valve is a full open, the rocker continues to try and open the valve but can't. Sooo...sometimes it will bend pushrods and/or break rocker arms

 

What lifters are you using, LS1, LS7 or other?

 

Sounds like not enough valve spring to me.

More likely that, than lifters or push rods.

 

One thing I know of breaks rockers. Mechanical limitations. The valve cannot travel. Which leads to either coil bind or ptv. Hence the questions. Pushrods would have to be long enough to bottom out the lifters and eat up the reserve spring travel (assuming a properly setup valvetrain) to cause a rocker to break

 

Jose, please explain broken rocker.
A photo would help tremendously.

Darth is exactly correct. Mech interference. Somewhere.....