I have a 350 Vortec crate motor 330hp. It has a flat tappet cam. I was told to run 1.6 roller rockers. I'm wondering would that change my cam profile? Is that what I want? I was told my stock rockers are 1.5s. I plan on running a TBI don't know which one yet. I have a performance intake from GM that all my smog stuff will work with. I am going to put smog legal headers on it too. So it is going to be controlled by the computer. I will have a custom chip built to make everything work together. I am just at a corner with the rockers.
Please help a guy out. I need your experience and knowledge.

 

Hey Greg,
i'm no engine builder(though those who are will chime in soon i'm sure) but your cam profile is fixed. When the lobes were ground down from a solid steel shaft they set em to lift the valve to a max height and to keep it open for a certain duration. This along with the angle between lobes makes up your cam profile and there's nothing you can do besides taking a grinder to it will change that.
The rockers, the way I understand it, take the lift provided from the cam and multiply to get your overall valve lift or opening from the valve seat. Getting 1.6 rockers would increase how much your valve opens and change the way your engine breathes for better or worse.

It always puzzled me that engine builders advertise a certain HP but usually only ship the long block. I've never bought one so always wondered if they told use what intake, exhaust, carb, rockers, fuel, etc that they used to get that number.

The point i'm trying to make is that your block has the potential for 330hp and i'm sure more but I would just suggest that you're careful on how you get the air in and out of the block to get all the HP's that you paid for, especially if trying to stay smog legal.

 

A little terminology correction: NO Vortec motors have flat tappet cams. They all came with roller lifters.
I think you're confusing roller lifters with roller rockers. Choice of rockers is not influenced at all by whether the engine has flat or roller lifters.
If you want to swap from 1.5 to 1.6 ratio rockers, You need to check for pushrod clearance through the holes in the heads (1.6 rockers move the pushrod cup in the rocker closer to the rocker fulcrum, and for spring retainer-to-valve seal clearance with the increased valve lift.

 

The 330 HP GMPP Vortec 350 came with a flat tappet cam and a pre-86 block. Be VERY careful about running 1.6 ratio rockers. Those heads dont accomodate much lift. The set I had was only good to .460 MAX before the retainers hit the seals. If you want a nice upgrade, go with Comp Cam's magnum 1.52 rockers (self-aligning type). Those are much better than the stock stamped steel ones, and will give more consistant lift at the valve.