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Discussion Starter · #1 ·
Why do people use the 2,5V6 heads on the 3,0V6 engine....?

I am thinking of maybe changing my Calibras V6 engine to a 3,0V6... but whynot just put the entire 3,0 engine in the car?
 

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The only difference to the head itself is the bore diameter.

3.0s have Sodium filled exhaust Valves, and higher duration cams.

According to EPC, the 2.5 in Ecotec(X25XE) form was reworked in the cylinder head to give more torque and quiter valve train than the Cavalier/Calibra C25XE
 

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pound for cc's.....

the 3.0 in a high state of tune will give more grunt than the 2.5 (obviously) there are many ways of making the 3.0 even higher, but the route aint cheap, noz is best for bhp for bucks around 700 will get u knocking on the door of 270bhp (with the 3.0),a set of gas flowed heads around 5-600 + fitting for 20 odd bhp, a set of cams are good for 20bhp, a chip will give a better ignition and fueling curve so 10ish bhp, a panel filter 3-4bhp a s/charger at 3.5k will give u 70odd bhp.

the 3.0 and 2.5 have the same block and i have heard of vectra's with 3.0 blocks and a set of cams giving very good results.

unlike the turbo lump getting big hp from the v6 is costly, as is cambelt failur and tensioners (having been there myself)

gav.
 
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