Which upgrades MK1 GTI 1.8 8v to 1.8t 20v

Hello, sorry if someone wrote this

i got a Golf MK1 1.8 8v and want to upgrade wngine without change it to 20v 1.8t
I got complete head and want to know with much i need to do?

Thanks all of you

Sorry not completely clear to me ( maybe it is to others) what you are asking.

Actually I think you are asking how to upgrade existing 8v 1.8 engine, question for others.

Sorry, this is what i mean
Using original 1.8 8v block and puting a 20v 1.8t head what i must change

Thanks