I am going to buy a set of of 8mm spacers that are "hubcentric to vehicle hub" to put on the front of my 99 Lexus LS400 and was wondering if anyone knew how will the hub stick out enough to fit inside my rim?

 

no, you will need a set of spacers that extend the hub out.
also you will be needing a set of studs, as there wont be enough thread let on the stock studs with that much spacer.

H&R makes good quality spacers+studs. you need one that is both hub- and wheel-centric.

like this.

 

Thanks Puredrifter. I already have the stock studs replaced with extended studs. I am currently using 15mm hubcentric spacers all around and wanted to go down in size in the front because the wheels stick out a little bit while the rear wheels are flush with the body.