Often thought about buying the GM 330 hp Crate 350 engine, might someday. I was just wondering what's involved in swapping the cam for roller cam, (lt4 hot). I read on another board (TBI) that with a cam (LT4) and 1.6 rockers you can make over 400 hp. Is it hard to swap the cam from a flat tappit to roller?
Also on the 1.6 rockers, you don't need to remove the heads to change these...Right?
Can the pistons handle this much power, from what I've read the pistons are the weak part of this engine.

Thanks for input, just seeing what's involved in the swap if I ever take it on.

Thanks, Matt

 

Hard? Not particularly. I assume you'll have your current engine for donor parts, such as roller lifters, anti-rotation spider, pushrods, cam retention plate.

Rockers are easy to replace. Right on top of the head, one nut per rocker. In fact, you have to loosen them to replace the cam, taking them all the way off is just a few more turns of the rachet.

You will, without a doubt, have to replace the valve springs if you go with that cam. This can be done with the heads on the engine.

What induction do you plan on running with the 330 HP engine? You do know that it uses Vortec heads, and your current manifold won't fit.

 

The vortec heads will have to be machined to work with the hot cam. Valve guides need to be machined down, and the heads need to be machined for the larger diameter springs.

 

Thanks for all the input, I hope to buy this engine by the end of the summer, then I'll be able to work on it over the winter. I am aware of the intake issue, If I stay with TBI, It will get the edelbrock performer, or the GM Vortec intake. I have access to a 1988 TPI setup, but the intake is like $400. Is TPI a good Idea for this kind of power, I know I can get a TBI from holley (670cfm) that will feed the engine, but I have not really looked into the limitations of the TPI.

Thanks for all the help, If finances allow me to do the swap I'll let you know how it went.


Thanks, Matt

 

Some will accuse me of bias, but I'll say this anyway.

Get the L31 shortblock (what the 350 HO uses). Put the Hot Cam in it. Get S/R Torquers or Sportsman II heads and pocket port them. Get 1.6 rockers of your choice (don't have to be self aligning like the Vortecs do).

Then you can use TPI or TBI of your choice, no special Vortec intake or base required (may need to elongate the center two intake bolt holes on each side - minor issue). Will cost about the same as the HO engine would to get it running. But, it'll come with valve springs that can handle the lift, screw-in rocker studs, aftermarket quality castings, make as much or more power; overall, you'll be less limited in upgrade choices.