engine lacking power

[nacho mcnova]

hey all was looking for some advice my car seems to be holding back really bad as in its at the stage i got my ass handed to me by a 1.2 corsa:mad: and a bit jerky through the rev range. just cant get to the bottom of it all plugs, leads breathers pipes etc all ok no vacum leaks or anything done a flash code and came up egr fualt but thats been disconected also found out its not got its original gsi head but a 1.4 sri head would this have something to do with it.
cheers to all whom reply xxx

[let_nova]

hmm. did you run it in correctly?

[dougie_boi]

yeah he run it in properly mate gave it a very easy 500 miles then i changed his oil for him then slowly built up speed for another couple of hundred miles mate

[let_nova]

any smoke? timing all ok? dizzy all sweet?

[let_nova]

plugs all ok? wip them out see what they look like.

[jimbob-mcgrew]

so youve got a 1.6 gsi engine with a 1.4 sri head on it ?

[nacho mcnova]

thats right mate, i bought the engine like that but i didnt notice it til the other day, i have changed the octaine plug and seems to be running abit better but still not getting full power especially through the mid range.