Problem with Chevy or Corsa Pick Up 99

Hello, good afternoon. I have a consultation.
I have a 1999 Chevy Pick-Up
when I bought it was bad of the engine, it sends it to the mechanic and it is tied its ring, I told me the mechanic that the engine of this truck is 1.6 and that the head it had installed is 1.4 and apart is cut.
What does this head affect me 1.4 in 1.6 motor ???

From the fact that I have given it more details and more and more ...
first I accelerated and still has that problem, a bell is heard when I accelerate in climbs and sometimes in line, sometimes it does not do it anymore, it is weird.
Of the accelerated, wash injectors, change gasoline filter, change oil just like the filter, change oxueno sensor, change acceleration body sensor and I don't know what else can I do !!!!
What do you think ???
I would thank you for your help !!!

The change to a smaller and more trimmed cylinder head is an increase in the relationship of compression

therefore will heat the engine
Greetings from Costa Rica

If it is accelerated the most likely that it is entering air on the other hand, therefore it is because of the IAC, Relay regulator, Czech that is not very open or that its orrin is bitten.

Thank you!!!
So do you think that causes me to accelerate at all times?

The IAC valve already changed it.
Another thing that happens to me is that Casacabeea a lot in some occasions when accelerating and other occasions does not.
I am currently spending a lot of water, I put approximately 1 liter every two or three/