I've heard that the LS400 from 90-91 had forged internals being stronger then the 98-00 with vvti. How much would it cost at the minimum to get the internals of the vvti to the standard of the original motor with forged engine internals?

 

1989-1994 has the bigger connecting rods. Unless you plan on going massive boost any UZ is more than strong enough.

 

Best place to ask questions is:

https://www.lextreme.com/forums/foru...uning-fiat.16/

This is mostly just an OEM+ place. All the poweradder guys are over on lextreme.

 

If it were me, and I wanted to take on something like that, I would just look for the first gen engine only somewhere on the market and then work with that engine block, then I'd work off that block that is known to be good. It seems to me a much easier route then swapping out internal components that are not originally native to the block. But that's just me, someone else may have a completely different perspective. So I would answer it what would it cost? The cost of finding a replacement 90-91 block, better yet complete engine and work with that. (as long as its good). I've modded a jeep one time and did all kinds of things to it and conversions, tore apart transfer cases, its okay if that's the challenge you want to take on.

 

If someone needs to ask a basic question about connecting rods they are not going to be doing any engine work.

 

^ yeah valid point lol

Also wait - OP, what do you mean by "stronger".

All variants of the engine are fine in stock trim. There aren't really any issues due to the engine not being strong. All the normal issues you see are from neglect or just standard stuff, belts, hoses, gaskets as the rubber ages over the decades.