La1 variants rocker arm differences?

[jaons_Wlp]

Upon investigation, the camshaft used in all 1999 and older La1 variants seems to be the same(using part numbers). So the power difference between the alero engine and the minivan variant must be something else. 15hp and 10 ftlb is too much of a difference to be different prom tuning, oem is too conservative. If it were a higher compression ratio being used then the power bump would have more torque increase and peak power would stay around the same rpm, not increase peak power up 500 rpm from 4700 to 5200. Its not the cam, so it must be higher ratio rocker arms then right? to simulate a bigger cam. It has to be. If so then this would be a good cheap mod for non minivan la1 variants. Searching did not help, someone smarter then i chime in!

[Guest]

Rockers are the same.

The rated differences are the tuning, exhaust and intake systems. There are no major differences between any of the LA1s regardless of year to change the power output.

[carbon]

Exhaust... the U vans didn't have stupid exhaust routing like the N and W bodies. There is no appreciable difference in any part of the actual engine. The GAGT and W-body cars got higher numbers due to a less restrictive dual exhaust muffler and the vans got higher numbers yet due to much simpler exhaust routing...

[jaons_Wlp]

Okay thank you, that makes since. I hear the 1.7 rockers on a 2007+ lz4 could work with little modification. Is that likely?

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[neophile_17]

Nope sorry. The LZ4 rockers are offset style. You may look at the LS* style rockers. I think these are straight but you would have to do more research.

[jaons_Wlp]

Damn.. If only gm didnt use stupid thread sizes for the aluminum heads. Thanks

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[1QUICKHATCH]

If you are looking for extra power the easiest is a tune and exhaust