Engine mount welding?

Whats the opinion on engine mount welding. I've never really wanted a lump thats been welded but that's only down to ignorance really as I don't know the facts.
Someone said to me the other day that if it's done properly, cleaned faces, right temp etc then it's as strong as the original cast.
I know studs are welded, ports are added to etc.
So what s the consensus on this peeps please.
Reason - I'm looking at a spare temp engine for my Li 150 (S3) while I rebuild the original. Then I want to use the temp to have a go at building a tuned lump after.
Cheers.
Someone said to me the other day that if it's done properly, cleaned faces, right temp etc then it's as strong as the original cast.
I know studs are welded, ports are added to etc.
So what s the consensus on this peeps please.
Reason - I'm looking at a spare temp engine for my Li 150 (S3) while I rebuild the original. Then I want to use the temp to have a go at building a tuned lump after.
Cheers.