I'm going to be arsey.
IMHO there is zero reason to build a 1550 cc turbo engine (how are you gong to do that anyway?) other than pub bragging purposes.
If you want more power concentrate on adding more boost reliably (well feed it more mass actually) without blowing it up.
here are a few more reasons why it is a bad idea
the bores will be paper thin and the power gains will be lost by bore flex. you need a very fat decompression plate to get the CR anywhere near sane for a TC engine, Your wallet is not nearly fat enough for the things you want,
You spend a fortune on a stroker crank, fancy rods etc and you will melt it at one point (because that is what high strung turbo engines are good at) taking out all the fancy parts and then you will be fed up. The gearbox will **** itself repeatedly,Somebody who does know how to do stuff will show up with an engine build from scrap parts that will eat yours.
these pipe dream projects generally work like this.
you have a ( in your mind great) idea, you don't have a clear plan but you buy some very nice parts, you start building the engine, after a long time you get it to run sort of, **** breaks, you run out of money, you sell the remaining parts at a great loss.
May I suggest this:
http://www.strojar.c....B.Heywood.pdf.
the question you have to ask yourself is the following .
given a limited space going bigger on the exhaust will have to come out of the intake. Ergo is the loss due to pumping losses greater than the loss do to compressor inefficiency due to the smaller intake valve. Also remember that on a turbo the compressors are coupled. you increased the exhaust valve but the intake has gotten worse. So you need more effort to get the air in and that is making it harder for the exhaust turbine to turn. the intake charge will heat up more, the exhaust will be hotter, the density and thus mass will be lower and it makes less power, it might produce more boost though, but not move more mass.
Coupled to this :by default the exhaust valve is way more efficient than the intake valve. so it looks wrong but actually it balances the intake and exhaust out a bit.