I was wondering if a 90 civic DX will fit a LS vtec engine I know if i try to do it there will be alot of complications. I know i will have to change alot of stuff.. but i was wondering will it be worth it? or would i rather go with a SI engine?

I just bought a LS Vtec 3 or 4 days ago and i was just wondering

 

No.

If you ask can a lsvtec be mounted inside of a 90 civic dx engine bay then yes.

 

Yes it will work in there. Please do a little research as this have been covered multiple times.

https://honda-tech.com/zerothread/1508680