I am a p plater and cant legally change my engine for another 4 years, I would like to know if it is possible to rebuild the Sierra 1.3 block with all of the gti componets, and then use the gti twin cam head? Any info would be great...

Yes - but it's going to be a lot more work than you think.  When you're done rebuilding the engine, you still have the intake, exhaust, fuelling, ECU, harness, etc.

But it is able to be done? Wouldn't i have to do all this anyway if i swapped the engine?

Yes, so you are in the same boat.  Do they require you to have the stock block or can you change them over and just claim they are both Suzuki 1.3L engines. 

But it is able to be done? Wouldn't i have to do all this anyway if i swapped the engine?

Is it able to be done - yes.

Wouldn't you have to it all - no.

Think about it - one is an engine swap, the other is an engine rebuild + an engine swap - one is defintely more work than the other.

Reading your original statement I'm guessing that you are from Aus. It sounds like you are trying to bend the rules a bit by claiming that you still have the original engine. My understanding is that in some states you can get a defect notice for a pod filter so a twin cam conversion is likely to be some way outside what you are allowed to do on a P-plate.

the blocks are the same, the DOHC does have a craddle on the bottom to hold it to the high revs. You won't be able to bolt up the intake and exhaust manifold to the DOHC so you might as well drop the whole thing in there. It's still a 1.3 so how strict are they? Can they tell?

With enough work you can probably make it look stock. Get the piece to turn the dist up and it'll fit right in and the power is unreal....when you hit 7K and keep going you will smile from ear to ear.

Reading your original statement I'm guessing that you are from Aus. It sounds like you are trying to bend the rules a bit by claiming that you still have the original engine. My understanding is that in some states you can get a defect notice for a pod filter so a twin cam conversion is likely to be some way outside what you are allowed to do on a P-plate.

Yes I am in Australia, and that is pretty much what I am trying to do. Im not too sure on the exact ruleing but from my understanding I am not allowed to drive a car with a mod plate or goes over 200kw

the blocks are the same, the DOHC does have a craddle on the bottom to hold it to the high revs. You won't be able to bolt up the intake and exhaust manifold to the DOHC so you might as well drop the whole thing in there. It's still a 1.3 so how strict are they? Can they tell?

With enough work you can probably make it look stock. Get the piece to turn the dist up and it'll fit right in and the power is unreal....when you hit 7K and keep going you will smile from ear to ear.

I donno if I would be able to just swap engines, wouldnt the engine number say that this engine is out of a black suzuki swift?